I noticed in a photo of David Kassan's subway demo he is using bucket seating. I never thought about it before, but it is a great idea for plein air painting because you can use the bucket first to carry your supplies and then flip it over to use as a seat. It would be cool to create a little cushion on the top for comfort and then a fabric insert to hold/easily remove your supplies. Maybe the insert can be zippered on top too... I have an 18" inch grape juice/wine bucket that would be perfect to try this out with!