Leica have been very successful with their black and white sensors in the Leica Q and M series cameras. Pentax have released one, and Phase have released a black and white digital back. In general if you want to try a back and white sensor camera its an expensive option.
With the recent Ricoh Gr back and white camera its now getting cheaper to get into this dedicated BW photography niche.
Now we are starting to see rumours about a possible back and white only Olympus OM3. This would be great if true. Its a risk but MicroFourThirds needs a bit of excitement introducing into the range, and maybe under the new leadership OM may take those risks.
