You guys beat me posting that 4005-6 lefty. I had the same thought of....HAS to be the only one, no?
I've never played a 4005-8, although they look beautiful. The prices on them are pretty up there. Even if I owned one, it would be too pricey to gig with.
That copy one on EBAY appears to be nice...but over $10,000 for a reproduction one seems insane.
I also think I would be afraid of 8-string tension on the early dual hairpin Ric truss rods. It just seems an invite to neck problems. The root on top is also a deal breaker for me. Would have to have the octave on top.