I would love to have widget abilities so shopping can be done from other sites as well such as a blog. i.e. the product is a widget and the checkout process a popup.
The widget would place the product neatly in a myspace page or a blog, the popup would handle payments. Do you think this is possible?

I do like this idea...

Possibly not have it complete the purchase through a pop up, but to direct them to complete the order on the checkout page of your site allowing them to sign in and so forth.

the other shopping carts has this functionality, maybe someone from viart can go overthere and have a look? It would be a great feature to be able to decouple the actual website from the selling process...