Ben,
We just returned from six weeks of painting in Italy and France and I loved using your box the whole time. Definitely the best engineered and simple to set up I've seen. I especially loved the pressure hinge that allows you to adjust the tilt of the painting simply by pushing or pulling it without any additional nuts to adjust.
Sincerely,
Scott Burdick (-:
(Note from Ben: If you're not familiar with Scott and Susan's work you probably should take a good look.)