I still have my OM2. They have interchangeable backs. I would like a 4/3 sized digital back for my OM. I could draw framing lines on the focus screen. You could tuck the electronics into the space where the film canister sits. Don't know where to stick the battery, though.
I know, ain't gonna happen. I sure like my OM, but I sure don't like 35mm film any more. (I still shoot 120 film on occasion.)
Like many ideas this one is not new. Back in the early days of digital photography it seemed like a natural moneyspinner to do this. See:
http://www.dpreview.com/news/2002/9/19/siliconfilmagain
This did not fly 10 years ago because it was incredibly complex to create reliably.
Much as some of us appreciate the flexibility of being able to use 'legacy' lenses on our m43 camera bodies, many of these lenses were never designed to focus light rays onto sensors at the optimal angles, unlike those specifically designed for this format.