I know KHS and Haro both make 650bs they come only in a Hardtail design and only one company makes a proper fitting front shock. MB action last year ran a big article comparing all three sizes 26 27.5 and 29…but they never gave a definite answer in the article however a guy wrote in a month later saying… which is the best? and MB action responded saying 27.5 is in their opinion the best overall size.
I’ll wait until a major company like Specialized, Giant, or Trek come out with a Full Suspension 650b…I may be waiting awhile though.