Like massive88 said, you should first look to see if you can power up by a keystroke.  Check in your bios settings for this.  Of course, this is only really useful if your CP acts as a keyboard and not a joystick/joypad.
Either way, how about a DB9 (serial cable)?  We all know those can handle many many connect/disconnect cycles, and they're crazy easy to hack.  Plus, you'll have a few more lines to use for expansion if needed.