thanks everyone.
What I want is a remote brick. Yes, Lookout can remote wipe, but I want nothing more than to kill the device so its unusable. From what I've gathered (I'm not certain because obviously I've never tried), the 100% sure way to brick a phone is to flash a radio meant for another phone. So, lets say I have the radio for the MyTouch 4G on the SD card, I could send a command that would activate an app that would automatically reboot into recovery and flash the radio, thus bricking it. I'm sure its possible.