Any digital rangefinder with interchangeble lenses that is NOT M-mount is doomed to fail! There are 100's of 000's of M mount and LTM lenses out there and to try to introduce a "dedicated" mount would not work.
Leica will survive a Nikon/Zeiss/VC/Hexar whatever digital. Their product line is still very good. However, they do not have access to sensors like the D3 technology and it is unlikely that Nikon will pass it on to them.
The M-mount is not protected by patent anymore and anyone can use it!
The "coding" of M-lenses is seemlngly tied in with the sensor in the M8 rather than with digital in general. Nikon or whoever makes the next DRf can easily include coding as a menu driven option.
Sensor size is critical. To launch a D-size or 4/3 sensor would be stupid as two years from now, the full size sensor will be the industrial standard and prices will come down dramatically in the next while.
Mp is of less importance as a12-15MP will do a very good job as it is. The critical part is a low-noise/high ISO sensor (D3 type, 3200/6400 ISO with very little noise).
What probably will happen (and I can be completly wrong here) is that we will get a couple of new entries in this field. A revamped M8 (big bucks and a limited market), another slightly lower priced Drf from a major player (Dont forget that Sony is in this game for the long haul too) and possibly (and hopefully) a RD-1 type Rf with upgraded sensor and better screen (though I would love to keep the "fold in" version of it).
Price range would be $6-8000 for the top of the line "M9" with an expensive name tag.
Second tier (pricewise) $ 4000-5000 all bells and whistles camera and a sub $2500 revised RD-1 type.
A Nikon M-mount is not as farfetched as we think as in 1946-47 they were contemplating a 39mm screw mount Rf rather than the Contax cloned one! Of course Nikon could easily supply an adapter for use of the Nikkor RF lenses on a body like that - and with electronic focus confirmaton, there could even be a SLR lens adapter (within reson - maybe up to a 180 fl).
My feeling is that between the Rd-1 and the M8 the RD-1 was the better camera from an ergonomic standpoint - particularly if you came from "classic" rangefinder back ground. The M8 is not as well designed in this aspect. It is slippery and cramps you hand, particularly with heavy lenses. You really dont want to drop that "M9" and the f0.95/50mm Noctilux!!!!!!
A DRf with a D3 capabiliry sensor for high ISO would also make the ultra high speed lenses less essential. If you can boost your ISO to 6400 and get ISO 1600 quality - why drag a F1 or faster around?