Hi Doodad,
A friend of mine is 6ft 5" and rides a 19" Kona with the saddle up pretty high.
I'd suggest not going for something like a 21" or 23" best, as for manouveribility, you can't beat a slightly smaller bike.
I'm 6ft and ride an 18" Kona, which I can flick around. I could happily ride a 19" or 21" bike, but whenever I do, it doesn't feel right.
I think as you said previously, if you're happy with the bike and it's set up then go for it
Cheers
Rich