No worries, there are a number of good mechs you should be able to field that will fit your criteria. Now, breaking down your criteria into a simple set of requirements:
1. Support mech - you've stated that short range and brawling are not your forte.
2. LRM's are your favorite and most manageable weapon, with PPC's and AC's being acceptable, as well.
3. Keep the weapon groups simple.
4. Having good torso-twisting that allows you to manage more with your aiming capability.
Keeping those things in mind, here are some recommendations for each weight class for you to consider utilizing. I will try to include at least 1 IS mech and 1 Clan mech for all weight classes . . . just in case you have a preference (or you ever plan on participating in Community Warfare).
Light Mechs:
1. Adder: They're actually a prime fire support light that doesn't use excessive speed to get the job done, but instead relies on supporting weapons. I use a 2x LBX/2 Build on my favorite Adder; but there are builds for 2x C-ERPPC, or LRM's. I actually use a 2x C-LRM/10 build with medium lasers for backup; and with the range of those lasers they function as good fire-support weapons, as well, for your purposes. Overall, they have good torso twist and are built for just the kind of roles you're looking for . . . and with just enough speed to get out of a tight spot when you need to (most of the time).
2. Urbanmech: Ballistics and 360 degree torso twist. Also, if you don't want to use the ballistics, you can always go for some form of PPC, instead. They intentionally limit their speed for the purposes of carrying bigger guns. Granted, the Urbanmech package is one you'd need to purchase with real money . . . so I'd probably sit around in smurfy's and tinker with the thing for a while to see if you can get something you like out of it, first. Unfortunately, however, no LRM's here.
3. Panther: While you won't necessarily be boating anything, you can carry a PPC and LRMx10 on any of these chassis with an XL 250, Max Armor, and 2 tons of ammo (but no jump jets). You can shave engine for ammo and jump jets; or you can sacrifice some tonnage from the PPC, for LRM ammo and/or jump jets, and put in a LL or ERLL in order to still poke at range. However, similar to the Adder, this mech focuses on longer range fire support over anything else. Not to mention that the 2x AMS build, with respectable AMS ammo, an ERPPC, and an SRM2 with one ton of ammo (as a last resort) will work for long range poking and protect you well from enemy LRM rain.
Medium Mechs:
1. You've already got the Hunchback on your roster. That's a good one to keep, and you've said you love it (awesome to hear). Oh, and there's nothing wrong with running the 4SP with LRM's. Also, since you don't mind ballistics, there are plenty of solid builds for the 4G or 4H that you should be able to run, as well.
2. Blackjack: This mech has solid torso twisting, and can carry either ballistics or PPC's respectably well. Not to mention, when they get around to giving us the BJ-2 (seriously . . . I want that variant), then you'll have one that can carry missiles, as well. I have a rather beautiful BJ-3 build that uses an XL-235 with a pair of PPC's, AMS, Max JJ, and 2x Small Lasers (for when something gets within that 90 meter minimum range and you have no choice). The BJ-1 is also a great jumper that can lay down withering fire with a pair of AC/2s mounted in it. If you don't want the Jump Jets, then you can instead swap out for the BJ-1DC that allows you to carry more energy hardpoints, but ditches the jumping (I have a 1DC that's a "Mini-Rifleman" that crams in 2x AC/2 with 3 tons of ammo and 2 LL). However, you may wish to avoid the 1X, unless you're going to use it to carry PPC's and move faster along the ground.
3. Kintaro: This overlooked mech can do an excellent job of boating LRM's while being respectably maneuverable enough to stay out of trouble. Also, with the array of hardpoints you can put on a few large launchers, or a myriad of small launchers . . . whichever suits your fancy. There are many solid builds for all of the variants of this mech that I believe would suit your playstyle well.
4. Stormcrow: This chassis has a myriad of builds for ballistics, LRMs, PPCs, or anything else you want to put on it. It's one of the most flexible and desirable mechs in the game for a reason. It also moves just fast enough to get you out of most tight spots and back to the protection of your team.
Heavy Mechs:
1. Orion: You've got missiles, you've got ballistics, and you can mount PPC's. While mostly used for brawling purposes (in a mini-Atlas configuration), these can be easily adjusted to be fire-support mechs. While they might not have as much torso twisting, they carry a very solid payload for their tonnage. It may be worth tinkering around with in Smurfy's, to see if you can do things with it that you'd like to pilot.
2. Catapult: You love LRM's . . . the Catapult is a near-given matchup for you. Stay back, and let the rain go. You can also utilize the K2 for PPC or Ballistic purposes (or the Jester if you feel so inclined to spend real money). They have great twisting capabilities, respectable maneuverability, and solid payloads. Seriously give these things a strong consideration. They were also in the top 5 for mech resizing, so they're not going to stay the huge mouse-ear targets forever.
3. Mad Dog: The Clan's version of the Catapult, in many ways. This mech is meant to be long range fire support. Use it as such and it'll be good to you. It has ballistics pods, boatloads of missiles, and plenty of energy for PPC's and whatnot. It's also surprisingly nimble for getting out of harm's way. However, while you have great torso twisting and plenty of weapons options, you don't have jump jets.
4. Timber Wolf: It's almost impossible to put together a good mech list and NOT have this chassis on it. You've got every type of hardpoint at your disposal, and there are some great LRM builds out there. You can work wonders of fire support with this thing; and you have surprising agility for a 75 ton mech. Just don't be surprised if people give you a hard time when you're using a Mad Cat in a non-meta fashion.
Assault Mechs
1. Battlemaster: There are variants here that are worth another look. Some Battlemasters do surprisingly well in a fire-support LRM roll. Unfortunately, no Battlemaster has a great torso-twist range, so that can be a factor in your choices. On the other hand, they are tough SOB's that can serve you well with the right loadout. You can utilize these things for LRM's and PPC's. Your torsos are just going to be crammed full of weapons and equipment.
2. Awesome: I know . . . I just suggested the "barn-door". However, you're not looking to brawl, you're looking at fire support. For that purpose, Awesomes can do exceedingly well. You've got some great LRM carriers in there and of course they're trademarked for being PPC boats. An Awesome 8Q with PPC's for fire support and small or medium pulses for within minimum range can wreck people's days. On the other hand, of course, the 8T, 8V, and 8R give you solid missile options that can also combine with PPC's to cover both facets of fire support. Seriously give these things a long and hard look. You may be pleasantly surprised. Oh . . . and they were in the top 5 mechs for rescaling . . . so they're not going to be the "barn-doors" forever.
3. Stalker: These things are walking weapons platforms. PPC's, LRM's, even a ballistic slot on the Misery. These things are probably the kings of fire support. Their smaller engine cap ensures that you're packing these things chock-full of weapony-goodness and slinging it down range. They're also great for doing this from afar, with boatloads of tubes of LRM's and space for backup weapons. However . . . they're slow, and they're not nimble. Stick close to the main body or you may find yourself in a world of trouble.
4. Warhawk: Currently its the closest thing you're going to get to a dedicated clan fire-support assault mech. You can get a pretty hefty number of LRM tubes on this thing, and they're also set up and designed for long range fire support with PPCs. You can also, if you see fit, set it up for carrying long range ballistics, as well. It's also a fair bit more agile than the Dire Wolf . . . so you're not utterly screwed if you get some distance between yourself and the main group. You'll also do a better job of keeping pace and sticking with the main body. All-in-all it's a solid choice for fitting your needs if you want a clan assault.
Now, with all of this said, I realize it is a LOT to take in. If you desire any further help, by all means feel free to quote any of this and ask questions, or send a message. I'm sure that if you also start narrowing down your chassis more you'll be able to get some excellent help in putting together builds to suit your specific desires/needs.
EDIT: Went back and fixed a myriad of typos and grammatical mistakes.
Edited by Sereglach, 28 August 2015 - 11:47 AM.