When I saw this, I wondered why Epson didn't use the easily available 12.3 mp Sony sensor. At the time the original R-D1 came out, it used the 6mp sensor Sony was selling to everyone at the time - most famous in the Nikon D70 and a couple of other Nikons, it also made appearances in a bunch of Pentax and Minolta models. I'm surprised that they didn't use today's equivalent sensor (the 12.3) in the update, choosing instead to stick with a 6mp sensor that is now only found in the 2 year old $400 Nikon D40.
Epson doesn't make the R-D1, Cosina does. That much is fact; what follows is sheer speculation:
Neither the Cosina web site or the Cosina Wikipedia entry give any evidence that Cosina has the immense engineering expertise in digital electronics to handle the supporting electronics to a sensor. If that's the case they might well have sub-contracted that out for the original RD-1 (perhaps to Sony?) and essentially bought the sensor and supporting circuitry as a plug-in module. If now they can't find any company to provide them with a higher-spec'd sensor module, or if the combination of Epson + Cosina can't afford or doesn't want to risk the bucks for such a module, that would be the end of the matter.
Perhaps the original RD-1 came about because of the personal desire for a dRF on the part of some very senior executive in Epson, who then approached Cosina as a (film) RF expert to see if they would be open to the project. At that time no one could actually be
certain how well a dRF would fair in the market place. Now they've seen the level of interest from the RD-1 and M8, and can see just how niche a product category this is.
I have the sense that in Japan there are so many long-time camera hobbyists each with a collection of RF lenses that there is a modest market for a dRF to put those lenses to use with. Such enthusiasts are often far more interested in a camera as an end in itself than in the pictures it takes, so a 6 mp sensor might past muster.
The price tag issue would of course be exacerbated outside Japan by the yen's strength against many currencies.
BTW: I happen to agree with Bernard that the 6 mp count is not a show stopper, as a detail resolution issue, esp. given the handheld use a rangefinder normally gets. What's more disappointing to me is the limitation of 6 mp for
colour (or tonal) resolution. I worked with a 6 mp, Sony sensor, camera for several years. When I have to work with those image files now, it's that slight lack of colour subtlety that chiefly disappoints. But even that's more an issue at low ISOs.
