Go with the 10mm Auto. ;^)
10mm may be a good solution. My RIA 10mm is a heck of a gun. The round is the same diameter as a .40 S&W and can be double stacked like a .40 and still keep the grip size relatively small. Also, if the .10mm were selected maybe ammo would be easier to find. Admittedly, Ive never done or read any comparisons between 10mm and .45ACP terminal performance.