For a replica custom US military style shoulder/tanker rig(s), see El Paso Saddlery in Texas. They do leather holsters like the older designs. I'm not sure if they do custom holsters for DA revolvers but you can check.
Lawman Leather Goods may have a cool shoulder rig. They had a treated black leather material they marketed for milspec/duty sidearms & outdoor revolvers. They make a leather Dirty Harry revolver rig; www.lawmanleathergoods.com
I'd contact them first before any payment or order. Some custom shops are backed up or a new purchase may take a long wait.