The Glock 29 is probably your best bet, dude. It fires a 10mm round, so you know it will put someone on their ass. here are the dimensions:
· Length: 6.77 inch / 172 mm slide

· Height: 4.45 inch / 113 mm

· Width: 1.27 inch / 32.5 mm

· 10 round clip

Go to a shooting range and fire some of the other subcompacts they have there. I'm positive that once you fire the glock 29, you won't want any other small pistol.