We work with the Pinnacle Cart system, and have used it to implement a nicely designed web site for a lingerie my wife owns, as well as other carts in other verticals.
The cart is separate from the skinning, so layout is very easy, integration is pretty straight forward. Updating the cart is very simple, and it can be tuned to be very search friendly and it has a great backend system, better than any cart I've seen.
Lots of great modules made for the cart, and with the proper planning it would be easy to roll a site out using this system.
If you would like more information, you can check it out at
PHP Shopping Cart Software | eCommerce Website Solution| Storefront Design | Hosted Shopping Cart | Online Store Builder. If you'd like for us to show you the lingerie site we developed, just shoot me a PM.
It works with the major payment systems, and there is even a discussion out there of integration the Amazon Custom Payment system as an option to offer your users 1 click checkout if they are amazon clients.