An idea: if you're going to DIY a cab, you don't necessarily have to stick with 84 hp. Raw Vector rails can be had in up to 300 hp increments. Now, that would be utterly bonkers, but one format I've seen from Erica makes a lot of sense to me, and that's 126 hp. It's big, but not overly huge to the point of either being overwhelming or unportable. Check out Pulplogic's or Synthrotek's offerings for rails and mounting hardware. And yes, 1U makes perfect sense; if you can shunt off a lot of utility functions into the tile row(s), that makes more space for the big stuff.