I had a box where I added some spare HAPP buttons to a motherboard box, and added some male/female RCA cables to the 360 pad and motherboard box so they were mapped to LB/RB. I have an iCade Core but no Dremel so I couldn't cut holes in that... but I had a spare iCade Jr. I never used and this motherboard box... so I wired up L&R flips and added nudge buttons and launch/down arrow. In practice, it actually works pretty well
Seems to be a bit of lag (and I may be mistaken, but slightly more on newer tables... Firepower was fine, but AfM seemed to have a little more lag).
Still, fun little way to play it when I'm at home! Will be adding magnasave/special buttons, but not worrying about menu navigation etc. Perhaps when/if I make a proper box for it.