Rolf,
The pistol I made was similar to your fantasy pistol.
It has a 9" long tapered barrel, 45 cal., percussion lock, single set trigger, and is a half stock. It has iron furniture, and I also cast a pewter butt cap onto the grip. Since it was going to be a target pistol, I checkered the grip and for fun added a little carving around the tang.
Looks good, but the darn thing never shot well. I probably made a mistake by using a hooked breech set up, with the rear sight mounted on the tang instead of the barrel.
John