Wow, This looks pretty clean. I would be very interested in seeing the workflow for staff filling out orders. I am also very interested in seeing how the inventory interface works in more detail.
There is an excellent opportunity to get some really excellent reporting built into the system.
The use of AJAX is very smooth. After adding items to the cart, do you have the concept of adding additional related items to the screen to help sell more.
Please let me know if you need assistance with testing or developing any new areas.
I am starting an assignment to look at this very thing for a retail jewelery store, so I have a lot of data to upload and test with.
Nice work!
Jim www.walkspoiled.com