Digital photography

why would you want a film back for an average film camera?
the market of pro photographers is non-existent: the quality of the film backs (note: excluding mamiya and hasselblad etc backs) would not match that of their digital cameras, and if anyone wants to use their old lenses (which is perfectly understandable) then adapters are available cheaply and easily for most brands.

as far as i'm concerned an idea like that is the worst of both worlds: complicated, low quality and expensive.

I couldn't disagree more. The whole point is that you wouldn't put it in an "average" film camera. And how do you know it would low quality and expensive? If it could output 12mp and RAW files, I'd be willing to pay for that.