I was looking for the same thing for my soon to be Shield in 9mm and I bumped into this youtube video with a gentleman that installed SA37 on his 9mm Shield. But my question is how was the POA/POI going to be with those full size sights on the M&P Shield in 9mm.
Smith & Wesson M&P shield night sights / crimson trace M&P - YouTube
I like those SA37 type of night sights from Trijicon.