Francois, thanks to you and to Jill for yr efforts. I'm going to pass on this and at some point I will likely buy an EUB directly from the maker.
The guy selling this as a "detachable neck" is a bassist with an impressive resume and schedule and is listed as a endorser on the Azola site (on the Lightning Bug list). I have to assume he had it modified. In any case, I'm going to back away from it--if any NYC area cats want to check it out, here's the link:
http://newyork.craigslist.org/brk/msg/92674170.html
asking price seems a bit high--but I'm no EUB expert (clearly!)
I played one of the older Bugs when a guy playing one locally let me sit in on it. I had the same experience you describe, notes disappearing up the G string.
Also, I have a Biesele which I love on my main gig bass and I might prefer a EUB with either a magnetic option or a traditional fingerboard end to mount a Biesele on.
Again, thanks Francois!