I'm 30 and 5-11 tall.
My 20 is a Mutiny Animist with a 21.5 top tube
I have a 22 Holmes (pictured on previous page)
I also have a ModelC, WaveC, and WaveC Prototype that I love.
The Holmes (22 top tube) feels like it has the most room up front, and has the shortest back end of the bigger bikes. It's actually really close to the Animist in terms of rear end length. The lower bottom bracket makes it feel real stable. The Holmes also feels much closer to a 20 inch bike. Out of everything, the Prototype WaveC is probably getting ridden the most lately. I just really love the 24's for some reason.
S&M makes 22 pitchforks with 990 mounts, so fronties are still doable on a 22.
If you're going to do a bunch of front brake tricks, I'd go with a 22 over a 24. I feel like fronties on a 24 feels a little weird. Bobby (skateparkrider) let me ride his WaveC with fronts when I was in Austin for ACL last year, and trying to use the fronts felt a little weird to me.
I'll throw this out there too, if anyone is ever in the Raleigh NC area and wants to try out some different bikes, hit me up.