check this site out, and click on textures.
As you can see… some nicer textures, such as the wooden crate which has a height map included, is going for 20.00 a pop. Alot of businesses in the 3D design/animation business will use these in projects along with some made in house.
not sure if you can sell through them… and take a cut or what, but you may want to try advertising at a 3D modeling forum and ask artists what they’re looking for. Then just sell them via your own website.
g/l