Thanks for the reply.
The lensbaby is nothing like a petzval. I have one of the new ones and I like it, but it's totally different. I actually like the plastic lens stopped down for a holga type effect if I'm shooting with the DSLR (sorry again).
I could adapt the wee petzvals for the 35mm format easily. That's not the issue. The problem is the image circle is so big that I would lose the edge effects I'm looking for. What I need is a lens that has a really really small image circle.