i am 6'3, i had 2 26" bikes, a connondale prophet size XL and trek fuel ex7 size L, now i own a specialized stumpjumper FSR 29er, i will never go back to 26" and i do agree that size of the wheel should be sized according to riders height not just by frame size, i think anyone under 5'9 should be fine with a 26" anyone above should not even consider a 26" bike, mainly due to center of gravity, if your tall as shit and your sitting on some clown sized wheels your going to be way too top heavy and take many handle flips, throw on some bigger wheels to balance you out and your ride becomes so much more confident.
Anyone 5'9 and taller, if you are not on a 29er you are depriving your self of the comfort and confidence that comes along with the bigger wheels, try one and you will not go back.