Don't break the rules on this forum. Installous is illegal and it's a hurts to app dev users (myself included). I not seen legal apps used from that.
Anyway icade send a key when pulled, and again when you release it. So a normal Bluetooth keyboard would not work, since I see it's a problem to send the relaeased key, which is unnormal (but required for iPad, due how it's work).
Imame works nice for my iPad 1 and works nice with icade too, litlle except its might have few ms delay in some(?) games (which can been annoying in imame, but not seen that issue in other games). Tested few roms, some can slowdown, other works excellent and some did work at all (due romset I have).
But imame is now removed (as excepted), but I did got it and tested. It's based on v0.37b5 with extra games from other version... Same version seen on other game consoles.
Ps. iPad is not jailbreaked.