You
can brawl in Yagerbombs with an XL engine. It's just more... exciting than running a standard engine. IMHO, the gloriously high, torso locked arms on Yagers make for a far better support weapons platform than a brawler, striker or skirmisher, but you can still wreck face as a face humper.
If you are steadfast in your refusal to turn the the volatile, vulnerable yet gloriously overgunned XL dark side, then maybe something like
THIS could float your boat. Mixing ultra and vanilla dakka gives you the best of both worlds, and the 4 MLAS are the equivalent of an AC20 round if you sport a steady hand. I've also found that even as a brawler, you don't need as much leg armour (it's your STs that attract all the hate) and even with drastically reduced arm protection, I find that I almost never have them blown off, as their frontal hitboxes are utterly miniscule.
It's not the fastest mech in the shed, but speed is the tradeoff you make in the name of firepower.
If you want to try a support role,
this is (almost) hands down (one of) my favorite machines: slow as hell, fragile and hot for the un-disciplined, but hits like a random passing apocalypse.