That looks great! And color from b/w?
I don't think I ever realized you didn't need chemicals to process the paper when you were done. Why is that?
Not that chemicals are that expensive, but I just don't think I would shoot enough pinhole pictures to be able to get the full use out of them before the developer would go bad.
With no chemicals, I would me a lot more willing to give this a try. Well that, and I drink enough beer to be able to get a couple of different scenes!

Just to double check, this would be using regualar Ilford Matt 5x7 B/W paper, correct? (normally chemically processed)