Any BlackHawk Serpa that you can get at Academy that is for the M&P weapons the only weapon that my serpa holsters do not fit is my new Shield 40 and they are about $29.99 just look online at Academy Sports and search holsters!
N82. While designed as an IWB I also use it as an OWB using separate belt. The M&P style in full size fits ALL M&Ps from my 9mm compact to 5" .45 ( don't know about Shield).
It has Kydex frame mounted on neoprene covered leather. By far the most comfortable and user friendly holster I have ever used.
It have no interest in the company except as a satisfied customer. They are a made in The USA in North Carolina and very reasonably priced. They seem to be happy to talk and answer questions either by email or phone.
Safariland 6377 and 6378 will do what you're asking for. I have a 6378. The gun is fully covered, though the end of the holster is open to the outside world.
I have one made by Dave Elderton at KyTac. It is specific for the 5" Pro, and won't fit a regular 4". It completely covers the barrel and protects the fiber optic sight. Since the slides are different widths on the 5" Pro, make sure whatever you buy will fit it snugly enough to retain the weapon.