Go 45. My favorite "N" frame shooters are my model 1917, model 1950 (pre-26) and model 1955 (pre-25). I have a real affinity for for 45acp revolvers. The 1917 is a real piece of history. I know they don't fit your criteria, but it's a mere suggestion. Any 27 or 28 with a pin in the barrel and recessed cylinder will do nicely. Good luck.