The R&D costs to get something like this in a usable state would be enormous, and I can't see there being much consumer or professional demand. While a nice concept, it seems pretty farfetched to make it to production. Also, it would pretty much have to be a fix-focal length camera without interchangeable lenses... or it could take Mamiya TLR lenses and suddenly drive the market up!

Seriously, though, I think it is easy enough just to carry a small digital camera for tests and sketches alongside an analog camera. It's what I do, and it ads very little weight or difficulty along with an awful lot of functionality. Still trying to find a good digital camera with a light meter accurate for film exposure, though... It seems like it would be easy, but they all seem slightly off, so I still carry an analog meter (or compensate in my head, when needed).