Misty is an employee over at Vassago Cycles.  She took a 29″ Vassago Optimus Ti and turned it 650b.  After talking with her for a couple month on her thoughts of the wheel size she did a quick review of the bike and how it handles.

Vassago Optimus TI 16″
Paragon sliders set forward
WhiteBrothers Magic80 29er fork
Velocity Blunt 650b rims on XT bubs
Pacenti Neomoto front
Pacenti Quasimoto rear
32×20 gearing
 
I am 5′2″ with a 29″ inseam.  I loved the feel of the 29″ wheels but it was a bit unwieldy and tallish
in the standover. The 650b wheels and adjustable wheelbase combined with  the already low standover of unique riding position of the Vassago makes for a perfectly handling bike for my 5′2″ frame and 28″ inseam. With the 650b wheels, the BB comes in at 11.5. This lower height actually feels proportionally correct with my smaller frame. I do experience occasional pedal strike, but thats due to my standard length cranks. The 165mm cranks will certainly solve any issues and actually fit my legs a bit better.

While not intended, I am convinced after several rides that the low standover, slack headtube, seattube and adjustable wheelbase of the OptimusTi make for a perfect conversion for a proportionate 650b bike.