I think there are commercially-made versions because I know people use them to connect Canon EF lenses to (for example) an Atik 314L+. This sort of thing, for instance:
http://www.teleskop-express.de/shop/product_info.php/language/en/info/p2836_Geoptik-T2-Adapter-fuer-CANON-EOS-Objektive---mit-Stativanschluss.html
The tricky part is achieving the exact back-focus required (46mm flange-to-sensor with an EF lens, I think). Well, actually the first tricky part is justifying the cost :)
I have sufficient bits to make one myself on my lathe, but I haven't got that far yet.
James