I realize this is a really old thread, but to those who might still play this adventure, I would suggest checking out old thrift stores and such. Today, my wife and I picked this odd statue thing up. It is just right at 6 inches around at the base and stands 19 inches tall.
With some clever decorating, I bet this could be made into Kyuss, I took some photos next to normal miniatures so you can get an idea of how large this is. I'll make my own square base for it.
http://i72.photobucket.com/albums/i168/ica171/Brandon%20Misc/IMG_4288.jpg
http://i72.photobucket.com/albums/i168/ica171/Brandon%20Misc/IMG_4287.jpg
http://i72.photobucket.com/albums/i168/ica171/Brandon%20Misc/IMG_4286.jpg
http://i72.photobucket.com/albums/i168/ica171/Brandon%20Misc/IMG_4285.jpg
Here's a Kyuss mini I just finished sculpting. I decided to give it a go sculpting one from scratch. I still need to prime and paint it.
I'll put up more pics when I paint it. I was pretty happy with how it turned out. The main issue I have with it is that the proportions ended up being a bit more stalky than I intended. It's a bit too much like a really evil jawa. However, all in all I think he turned out pretty good, and once it painted I think it will look suitably badass.
Wow, I thought your Ulgurstasta was good, but this one is absolutely excellent.