Hmm I haven't seen too many of these in the "trading market" either. I know they were released in January 2006 as a Host only prize (during a Maze event? not sure.. ) along with the Grand Californian Pin during that month.
Anyways, it's been about a year since it's been released/retired, so people who have them should be looking for a good set of rare items. But, of course, since the doors aren't as "popular" as other old Host prizes (ie: Grand Cali/Floridian pins), so you could easily get away with trading a few regular quest pieces for a set, as long as you can find the right people to trade
OT: Ah, shoot, I finished typing this awhile ago, but I forgot to hit reply lol. At least I kept the window open..