I used to work with a fellow named Paul Lozano, and he would produce these lovely paintings and sell them for next to nothing. Of course, they were often painted on cardboard with no priming of the substrate involved- we would give him a hard time about that (hey, we worked in an art supply store! We were educated!). I'm looking at the one that I have proudly owned for several years - a painting of Egon Schiele painted on a piece of press-board from the back of a ready-made frame - and I'm wondering, so what's it going to do, without its properly gessoed substrate? EXPLODE? No, I guess it just might not last 500 years, but then, neither will I. Clearly.
Paul moved to Mexico City a few years back, and judging by the photos I see on facebook he's having a grand old time. Photos can lie, mind you- he may be suffering. (How are you, Paul?). Here are some of his more recent paintings: http://www.facebook.com/media/set/?set=a.10150730150815046.715538.683535045, and here is his blog where he sells his beautiful handmade ties: http://mexicocitytraffic.blogspot.com/. If he has his paintings online somewhere else, maybe he can let me know.