Multiple users idiot-free system?

I would like to set up stock photo site, and to include many people in uploading photos and making products out of it.
Problem: each user should get access to his own folder in "downloads" section, folder in "products" section, maybe even a sales report related only to his downloads/products, so he/she can not mess up my entire site by erasing other people's downloads/products.
Mentioned before, but can't be emphasized enough: multiple image upload (into "downloads" section) would be extremely helpful...
Any modules for that purpose?

Not yet, but there will be made by Fido-X.