I have been following the thread with intense interest, but I have questions. I checked out the Mini35. What a fantastic tool. But the cost is somewhat extreme, and I was wondering what tradeoffs would one encounter if you were to machine an adapter plate, similar in concept to the plates that allow, say, a Chev 350 to be mated to an early Cadillac transmission, which would use the Canon mount on one side, and the 35mm mount on the other? You would lose the auto features, of course, but, assume that you were willing to set the various parameters manually, would this kind of setup work? And, if so, what would you lose?

I can't answer your question but I can give you another tip:

Here at the boards guys started making their own 35mm adapters (still do, btw) and one of them had a commercial succes with it.
It's now called the Micro35 adapter, or M2 (new version).
A complete set (I think with lense and case and stuff) costs like a tenth of the official Mini35...
Gives the same results, exept that your image is being recorded upsidedown, but you can just reverse that in your NLE.
Worth a try?

Wow! What a huge gift to the community! Man, I am totally psyched. Got to get me one of those!

What you describe doing will technically work, but you'll get none of the DOF advantages of the lens. In fact, the focal lengths will be off by many multiples because of the much smaller imaging area (1/3" versus 35 mm.)

Btw, Roy, Joseph's comment was on your initial idea, not on the micro35 adapter.

What Mathiew said. ;-)

The mini-35 relies on a relay lens to provide the 1/3" sensor with the 35mm lens' "projected" image.

Ah, the subtleties... I thank you for the information, although I am not exactly sure that I understand the cautions fully. Enough that I know that an answer exists, that it is very affordable, and that my DP will be able to play nice and make pretty pictures.
I love this board!