Not all that cheap, but
THIS is how I currently run my 4X.
I love the punch of 2xAC10s and the truck load of ammo to back them up. Why bring an auto cannon boat if you're gonna click dry half way through the fight? The SRM4 pack lets you do increased damage up close and gives you a nice scatter weapon to help with lights (the bane of your existence.)
The machine guns are almost an aesthetic choice. I'm not going to tell you some fish tale that they actually do great damage or anything, they don't. But they do help you gauge a scout's lagsheild and are very satisfying to blast away with up close. Between the cannons, the SRMs and the guns, if nothing else you make a hell of a racket.
You could put some lasers in their place, but I don't like that. With the 250 engine and the super low heat weapons, this build doesn't need ANY heatsinks. You get to save that tonnage for weapons, ammo, and speed. I think even a pair of MLAS would probably pump up the heat to the point where you would need a few sinks.
Despite the goofiness, this build does work well for me. You have the capability to do tremendous damage with the equivalent of an AC20 hit, but with better range, reload, and ammo count.