Though youre right, it is badass...
Its not really anything that special. (Parts wise at least) Its a mishmash of 60s and earlier HD parts. Panhead lump, VL(?) frame, early sporty or maybe triumph front end, trailer fender, old Bates seat, etc... You could build that entire bike from EBay finds. THOUGH, it certainly wouldnt be cheap.
Definitly a cool scoot though. In all actuality (and I could be wrong) it may be a survivor bike from back in the day that someone with pockets full of Yen had shipped over. Though there are some interesting bits that look one off, and Japanese in design.