Yes, there was a time when I was seeking to sell mine off. That was about 12 expansions ago, give or take. I actually sold enough other games that it allowed me to hang on to this one. I didn't get a very good offer anyway. The best sale was my entire Munchkin collection, which was considerable, and was purchased by our own Scott.
Selling it a piece at a time would be the way to go for maybe a few of the expansions, the rest would be difficult to move, I'd imagine. Selling all at once to someone who doesn't have any of it seems the way to go, but it would almost surely be at a considerable loss.