I dont find much difference in carry between the 2" and 4". Sounds like it might be weight is the problem. I used to carry a 4" M12-3 S&W with a 4". Very light and concealable in an IWB holster. A 2" version of the M12 might be just the ticket for you. It is a 38 Special but the +P 158 gr SWCHP is fairly powerful. Light use of +P did not hurt my M12.
Other than that, the short SP101 will work well. I find the shorter barrels throw the shot charges better. The 44 Special Bulldog worked the best with shot loads.