For a old school model 19 S&W revolver, I'd check www.Deltaforce.com
for the Aker comfort style shoulder rigs. The Aker model is very good and comes in brown or black leather. I'm not sure about off side pouches but you may them directly from Aker for the shoulder holster.
Galco rigs are highly rated. DeSantis & Bianchi may have holsters you'd like. For field or outdoor use, I'd lean towards a basic black nylon Bianchi Ranger holster. They sold a X and Y type harness but I think Bianchi(now a part of Safariland) only markets the x shoulder harness in the US.
The black treated leather STU shoulder rig from Lawman Leathergoods; www.Lawmanleathergoods.com
could do well for extented outdoor conditions. They are not cheap but have a lot of + reviews. They market the "Dirty Harry" shoulder holsters.
ps: for general carry of K frame DA revolver, I'd look into the Bianchi UM84R models. The flap style milspec holster could protect your 19 4" and be worn different ways. I don't think it fits the Bianchi M12/UM84 shoulder rigs but it works with other system belts/pouches/etc.