Movie Prop collecting is one of my hobbies, but it's one of those things that most folks probably don't think about or are even aware exists. Since I've had so many visitors that are Star Wars fans and visited for the Revenge of the Sith - Episode III trailer, I thought you might appreciate this:
Click on the image to visit the Master Replicas site and see more images and info on the AT-AT from Star Wars - The Empire Strikes Back (Opens in a new window).
These aren't cheap, but there will only be 1,000 of them made and I'll bet they sell out fast. I own a number of their prop replicas and I'm here to tell you the quality is excellent and the detail is amazing. These are also signed by ILM special effects guru Phil Tippet.
A while back I purchased a signed, Limited Edition version of Aragorn's sword Anduril from Lord of the Rings that had a run of 5,000. It sold for $250 and now they go for between $600-700 on eBay. Of course you can't predict these things, but I wish I could afford one of these bad boys...