Our shopping cart allows you to import products via CSV and manage from an admin area. You get full html and ftp access to change the look and feel of the site.

We do not give access to the full source code, but considering you did not want to go knee deep with OSCommerce, this might not be a bad thing.

Corey's article on merchant accounts should be able to help you. We have our own merchant account services, but our cart integrates with many other payment gateways.

I hope this was helpful to you. If you have any further questions, please visit our website and give one of our ecommerce consultants a call.