After instigating a new discussion concerning the Dirt Rag article on 50/50's on mtbr.com , I have started to come to the conclusion that even a 50/ 50 bike has issues, just like a 29"er, due to the large front wheel in small sizes. It would appear that in seat tube sizes of 15" or smaller, the front center of the bike would need to be compromised to such a degree that the bike would become a poor fit for most riders. Adjusting the head angle to compromise doesn't help, as the handling would be waaaay off. The smaller rear wheel isn't really necessary, from a fit standpoint. (Nor from a performance standpoint, in my opinion) It would seem that, at least in the smaller sizes, the front wheel should be a 26"!
My conclusion then is that 50/50 bikes would initially seem to make sense for smaller folks, but after examination, they suffer from the same problems as a 29"er for people 5'5" or under. For folks larger than 5'5", the full benefits of 29"ers are always better than 26"ers, so there really is no need for 50/ 50's at all. The argument that the 50/50 affords the benefits of both wheel sizes in one bike is selling snake oil. I don't have a problem with people liking 26"ers, they have attributes that some folks really like, or are just accustomed to. However; by just adding a larger front wheel, you haven't magically entered into the world of 29"ers. Most of the work on a bicycle is done by the rear wheel. The full benefits of 29"ers are only to be found on a bicycle that has two wheels measuring 29 inches, not one. If an individual doesn't like the feeling, doesn't percieve the benefit, can't figure out how to make it work, or- yes, I'm afraid too say- too short, then 29"ers are probably not your cup of tea. That's okay, there are tons of great 26"ers out there for you to ride and have fun on.
Just don't try to tell me that a 50/ 50 bike is somehow the embodiment of all things good from both wheel sizes. I ain't buyin' that crap!