"I cannot for the life of me understand why S&W hasnt made a run of classic Model 45 .22 M&P copies.

"For that mater a Stainless steel version of the classic Model 18 and 17..."

S&W did make stainless versions of the 17 and 18. They were Model 617's and were made in both 4 and 6 inches, without the full length underlug on the barrel, for Ashland Shooters Supply, who was then a fairly big S&W distributor.

I wish they would make more. I think that full length underlug is real overkill in a K frame .22.