Back to the point you made earlier then yes considering selling now to gain maximum returns might be a good idea. As quick as 650B was lambasted as a marketing ploy I'm surprised that as many are now accepting and looking at them for their next bike, so will your 26er be as covetable next year or the next, probably not. I guess it all depends on how often you change a bike? I don't see 26" parts becoming obsolete anytime soon though.
FWIW I'm on the 29er bandwagon, I'm on my third and for me and the terrain I ride they are faster and more confidence inspiring than any 26er I've ever rode, and I ride lots of different stuff, including tight and techy, steep and rocky as well as the more sedate stuff. I still think 26ers can be more fun if you like jumping and popping off things and of the 650b bikes I've saw they look promising.
FWIW I'm on the 29er bandwagon, I'm on my third and for me and the terrain I ride they are faster and more confidence inspiring than any 26er I've ever rode, and I ride lots of different stuff, including tight and techy, steep and rocky as well as the more sedate stuff. I still think 26ers can be more fun if you like jumping and popping off things and of the 650b bikes I've saw they look promising.