Below is my 6" 686-3 I bought new in 1989. I would also like a 4"er for the lighter weight and quicker handling.
If you are getting a new production 686, look along the top of the frame/barrel junction. Some of the new ones are leaving S&W with their barrels misaligned with the frame.
I'm not sure if the barrel installer is twisting the barrels too much or not enough, but I have seen more than a few NIB guns at gun stores with this issue.
Edmo