IIRC, we had a thread here a year or so ago with a link to a '9mm Mauser' discussing the straight-wall 9mm Mauser C96 cartridge (based on the 7.63mm cartridge) & pistol...I can't find it now, but it must have been interesting...
Wiki mentions it -
http://en.wikipedia.org/wiki/9%C3%9725mm_Mauser