I agree with Terao, a B&W with good noise characteristcs would be a great camera. SLR or RF. I assume your DM3A is an SLR after the FM3a?
Since most RF is B&W (just look at the random pics on the header page), I don't see it as a drawback. In fact if Zeiss is so proud of their lens resolution, maybe a B&W sensor would allow their marketing people to say that RGB sensors can't cut it right now, but a B&W sensor can exploit their lenses.
dRF is a niche market, we're not talking about dRebels here.
Who knows, maybe Mr. K could swallow the idea of a B&W sensor.
My thought is that if one of the smaller brands, like Sony, Sigma, or p-sonic want to get some street-cred, they could come out with a dRF. That is what Epson tried to do, but the marketing wasn't there. How about a dS3 from Nikon?
I have a 20D, but Canon I think has really dropped the ball lately. Their penance should be a dP RF with a FF sensor.
If refurb'd RD-1 are $1500, I wonder where the used market will be in a year?
Mark