Okay, this might be stretching exotic; but, how about an Enfield Number 2 Mark I** Revolver made in 1943 by a Scottish automobile and bus manufacturer???
Well I thought I would add these to your exotic gun pics, not sure if they qualify but here it goes...
The first is a EWK barrelled Dan Wesson model 15 357 magnum heavy shroud with a AR flash suppressor on the end of the barrel...
The next two pics are of a Caspian Custom build with different parts from Wilson Combat, Cylinder & Slide, etc on a Caspian Recon frame and Caspian slide. Ask any of the guys who have shot it at the NWI INGO M&S shoots, it is fitted like glass.... and completely ambi...