You can ride brakeless trials on everything, on 26, 24, mod is a good choice I think, because it's handy. You can ride brakeless trials even on street-trials bike.
The inspiration for going brakeless, I get from Flipp's and Carl Hopps videos. Also very like Ali C on 26 inspired and Mark W and Stan (summer 2010 vid).
First time without brakes were feeleing really unusual and interesting, but after 2 rides ( I tried to do rear wheel hops straight on flat, without trying on slope first, and it was REALLY FRUSTRATING and I thought brakeless is not for me) without brakes I set my brakes back and feels happy.. only for 15 minutes, and be bored untill end of that ride, next ride I took my brakes off again, and now I don't need them anymore.
Someone said that you first must get good with brakes and then ride brakeless - no, you shouldn't. When I went brakeless I was able to do only pedal kick and pedal-up.
Well, if you like it - do it, but just remember - it's not easy.