Hey... this sound really useful. We too would like to present pictures to the user to buy. Gallery2 is really nice in presenting art to the media, while ubercart has all the shopping cart features.
The code looks impressive... but I have no idea what does it say .
I am (almost) at the level of downloading modules, activating it, and pressing checkboxes... .
So please "hurry" and share your work with the rest of the universe...