We love building multiple store configurations in Magento. As clients get comfortable with successfully building and running an e-commerce business, they often want to create more stores, or — as in this case — create a niche online store to sell a subset of the products they offer.
Rust Experts is focused on being just that: experts on products to fight and protect against rust. It is one of several stores operated on a single Magento installation. We have not found another open source platform that handles multiple stores quite as well, particularly in terms of managing multiple payment gateways, shipping accounts, etc.