Do you know how rare it is to have a "canned" shopping cart with the ability to fairly easily do complex pricing options on a single item? Maybe you do, but if you don't... basically, they don't exist! I have looked. Everywhere! And the few that might even come close to the functionality that you have in CornerStore cost a fortune!
I just wanted to say that yours is the first product that I've tested so far that hasn't failed on handling uploads. This is going to work for a print company, so they are handling nothing but large files and all the other solutions I've tried so far have not been reliable. So far yours has been 100% successful in my tests.
The work, the thought and the organization you put into this app is incredible.