Erwin Puts is a prolific and controversial author and reviewer of Leica cameras and lenses. Like with most professional reviewers, you often have to read between the lines of his reviews since he makes a good deal of his money writing for Leica. Nonetheless, he's uploaded a fine review of the Epson R-D1 digital rangefinder.
My own take on the R-D1 is that it's brilliantly flawed. Kudos to Epson for proving it could be done. But the R-D1 is much too expensive ($2700 in Japan) and early indications are that its mechanical reliability doesn't match the price. We're already getting reports of viewfinder focus drifting and the analog dials sticking. Epson should be providing these cameras with a 5-year guarantee given what they're asking for it.
I hope that the new Zeiss-Cosina collaborative venture which gave us the Zeiss Ikon will give us a next generation digital RF. It has to be absolutely sturdy and built to last at least 5-7 years of professional use. My own dream would be a digital Hexar RF or Zeiss Ikon. They both have the mechanical guts to please any rangefinder afficianado.