For years, SiG-Sauer made a fabulous SAA that was imported by Herters among others. In the SASS world, the Herter/Sauer SAAs are considered some of the finest ever made. They, along with some of the older ones made by Herbert Schmidt, are classic German handguns. Each one was individually proofed and they were made with typical German craftmanship.
I know that the tools they used are probably still sitting in some warehouse gathering dust and the patents on the SAA ran out some years ago I imagine. With the increased popularity of Cowboy Action Shooting and Speed Shooting, I'd think they would be a natural. They could make ONE frame, Two barrels and four cylinders and meet just about every need. If they incorporated a barrel swap capability similar to Dan Wesson they would have the most versatile handgun on the market.
The ideal kit would be a frame, the 45 and 357 barrel, and the 357Mag cylinder (38spl & 357Mag), the 9mm cylinder, the 45acp cylinder and the 45LC cylinder. Put it all in a nice aluminum carry case and you'd have the best package out there.
Here's a photo of some of my SAA's from Germany. The top two are a 45LC and 44Mag from J. P. Sauer & Sohns and the bottom is a 357Magn (it was made before they standardized on Mag ans the abreviation for Magnum) from Herbet Schmidt.