I'm looking into building a web app that allows multiple e-commerce stores to coexist on the same installation and lets allows each individual vendor manage their own products, pricing, sales reports, etc. I know that there have been a number of previous questions on the Stack regarding the best shopping cart software, but this is a bit of an unusual twist and I couldn't find it answered elsewhere.
Obviously, open source is better from a pricing standpoint, but I've got no problem with spending money on a quality product that meets my needs. The ideal package would allow each store to be uniquely skinned, would minimize the amount of time that it takes to get a new store up and running, and would include payment gateway and shipping integration.
I've run across a few things in my scouring of the web, but haven't found "the one" yet--I know that osCommerce sort of supports what I'm trying to do, but I'm looking for something designed with this functionality in mind. Any ideas?
Thanks!
Justin