I had a "Jack Russell" once - one of the best little dogs I ever had. And . . . he wasn't a holster but he sure was a "pistol"!
Check over on the leather forum on CAS - lots of good holster makers over there.
If a pair of '51 Navies were good enough for Billy Hickok, then a single Navy on my right hip is good enough for me . . . besides . . . I'm probably only half as good as he was anyways. Hiram's Rangers Badge #63