Having a rack way out front like that, with a fork that appears to have a normal amount of trail, with a disc-brake up front = recipe for endo's.

That thing looks hot though. I'm with you, I love the look of big fat 650B tires.
I'm still laughing at when Rennick was riding my MTB and kept grabbing handfulls of brake.. it was like a bucking bronco!
Speaking of which, there's a good chance I'll be selling my Jamis Dragon Pro at some point if anyone is interested. Nice steel frame.. Juicy 5 brakes.. XT drivetrain.. Fox fork.. etc.. It's a 19".