I'm joining this thread, have to say Dave is my favourite Muppeteer, and just such a totally brilliant guy. I have never seen a Gonzo appearance, TV show, movie or anything that i haven't laughed at, and its always such a great moment when you see Dave himself in interviews and Gonzo performances. It's like watching the master at work, and he can adlib with Gonzo better than the writers can come up with lines in the shows!
I'd love to see him do more stuff, i know he voiced a Disney ride at one point but he's just so brilliant. He would have been great as a creature in the Harry Potter movies.
If i met Dave, i would offer him a complimentary Muffin without question!