Hmmm this is a very interesting line of thought Øyvnd & John. I'll have to do some experimenting this weekend. I'm want to put together a basic cardboard mockup that will slide inside itself so I can test the copy lenses I already have.
Dan - I talked with Reinhold and he is working on a 1000mm FL lens for another client so I'll be following that closely. I am curios about the overall sharpness. I like the soft focus look on some images but the projects I have in mind call for a sharper image.