Take Remington 357 maximum brass and 17 Mach IV dies, and you end up with a 17 Mach IV Rimmed after trimming to length <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> So easy to do, it's not really even a wildcat.
The Contender folks do stuff similar to this all the time. Another favorite is the .300/.221 Rimmed i.e. Rimmed .300 Whisper.
Scott
