I'm looking for plastic folding stands for painting. The idea is to put e.g. plywood board at the top of those and paint furniture on it. Any idea where (e.g. web store) I can find these?
All home improvement stores carry plastic and metal folding sawhorses that would be perfect for your application. Prices can vary widely, but I have found cheap ones to do exactly what you are thinking about at Wal Mart hardware dept and on occassion at Big Lots.