The X500T is pretty cool, but like Billy points out, the one they really built for Dave (I believe it was called the X550P...?) is the one I wish would have gone into production - as close to an actual 50's X500 as a new guitar could get, except for the Duncan P90's. I pawed Dave's, and they really got it right on that one - I'd leave my own old guitars at home for something like that too.
At least one, other than Dave's own, was built of those, Buffalo Bros had it for sale on their website.
The X500T was basically a standard modern X500 with two P90's (the neck one too close to the fingerboard, btw...) and a Bigsby.