I wouldn't be surprised if the 3'' J frame had been available in the past. However most people consider that the hammerless type is intended for pocket carry, which is not so easy with a 3''.
The S&W Model 640 and 940 were both offered in 3" variants and produced in both Standard and Performance Center runs, if you look around you will find they show up for sale periodically, they however do bring a premium resale value as they are not as common as the 2" variants.