I just saw on ebay the actual model of this for sale for 19K
search : "Star Trek Prototype" to see it
I'd be very skeptical about buying that without some kind of proof that it is in fact the original mock-up created for the show. There are a lot of talented scratch-build modelers out there.
Yeah, it's the one I built for Voyager back in 1994. Left it behind in the art department like a dummy.
The guy who must have grabbed it initially and put it up on ebay ages ago was connected with the Trek DVD productions, particularly the cast and crew interviews.