That sounds interesting do you have any info on who makes a .357 auto(thought thats why they created .357 sig).
Magnum Research makes the Desert Eagle in .357mag, .44mag, and .50AE. But then, the sheer size and weight of the thing really stretches the definition of "handgun."
The .357mag really is too long for easy inclusion into the grip frame of a semiauto intended for human hands. The rimmed case also adds a measure of difficulty to feeding. Hence the creation of the .357 SIG for use in more normally sized handguns.