For the 1911a1 pistols, you can find a few military holsters in leather or milspec nylon.
The old style GI flap rig is no longer issued but a few custom shops still make it. Check with El Paso Saddlery or maybe Mernickle. I'm left handed & didn't like the low position of the holster(I used it in 1990 while on active duty in Korea).
The Bianchi UM92 or milspec M12, made for the M9 9mmNATO could do very well. The holsters come in black, OD, woodland camo, digital camo. You can also modify the holster to carry it; SAS-drop leg, crossdraw, shoulder, chest(tanker).
The M12 has a removable flap too. The only - of the Bianchi holsters I'd say is the sharp metal attachments that may dig into your side. Ouch.
Clyde
www.bianchi-intl.com