Magento

I believe the one feature most shopping carts lack, and the most likely to make a shopping cart great is a supplier interface.
This would allow approved suppliers to create and edit their own products, lightening the load on the administrator.
A second part to this would be a supplier profile, where each supplier has a general quality rating.
A final part to this feature would be the ability to subscribe/import an xml feed from a supplier’s website into the available product listing.

This would give a shopping cart a more general usability for larger corporate clients such as myself/