Yeah, the very first Kodak digitals were just backs put onto F3s. Then came the Fujix, then later Kodak digitals on F5s. These digital modules were huge though and had tiny sensors.
The Kodak DCS Pro 14n and SLRn were excellent sensors stuffed into what was basically an N80 body with a bigger battery grip. That SLRn is still hard to beat at native ISO, even today. This is where Kodak discovered the "Italian flag" aberration found in superwides then invented firmware to fix it.
Leica noticed the same thing with their wide angles in the M8 and especially the M9 just a few years later.
As for the old cameras and hypothetical digital backs, the F5 is a perfect platform. It already has an unused serial port built in to the body to interface with some kind of data or 250 exposure back. The camera can talk to the back and serial is definitely enough data to control it.
Leica did it with the DMR but that was a few years ago and film was still much more prevalent.
The real problem is that if Nikon somehow managed to stick a full frame sensor into a back that was the same form factor as one of their thick data/intervalometer backs, you would have the F5 adherents clamoring to use the thing on their favorite camera (or almost favorite, you know what I mean.)
Nikon can't make money off of an F film camera any more aside from the small existing stock of the F6. Selling a product that is backwards compatible with deprecated technology is simply bad for the money making business. This is why they built lens incompatibility into the D40, D60, D70, D90, D200 and D300 bodies (these are the ones I personally have experience with, I'm sure there are newer bodies that have similar or greater incompatibilities.)
I don't follow this logic.
Digital backs were never a shipping product to begin with.
Nikon scanners, on the other hand, are a product line in wide spread use even today.
There are literally untold billions of film images that did not cease to be relevant with the advent of the digital camera!
I suspect the termination of Coolscan production was a "bean counter" decision that did not consider any other factors other than cash flow.
Cash flow. Exactly the point. Just because you think that a Coolscan 9000 is perfectly relevant, doesn't mean that Nikon and it's share holders do. Personally, I think a 75mm meniscus lens is relevant and I want Leica, Zeiss or Cosina to make one, but it's not going to happen.
It's all because they can't make any money off old technology and that is why they discontinued their scanners. Offering a scanner is simply telling a customer to buy one scanner to use for 10 years with their old F2 (or whatever other film body they have) and to NOT buy 3 or 4 new digital cameras within that 10 years.
Phil Forrest