I think that's wonderful! For a while, there was a line of bags that were made from misprinted candy wrappers. I'll have to do some research when I get back into town to see if they still have something like that. Over at the Polynesian, there were some jewelry offerings made from sustainable materials like bamboo and coconut. Probably the neatest one that i know is still around is at the Bead Outpost in Epcot, many of the beads there are made from recycled Disney maps. With that exception, if you're looking for eco-friendly merchandise, Animal Kingdom usually gets the bulk of it before it shows up elsewhere (if it does at all).
Oh, and a word on the Harvey's seatbelt purses -- although they are awesome, they are not recycled materials, with the exception of their Treecycle line. Everything else is made from new and not reclaimed or recycled materials.
Out of curiosity, would this be something that you'd like to see a blog post about on TouringPlans.com? I'm always up for a research trip that involves window shopping!!