For anyone who is in a similar situation, I am booted off of my Other World Computing mercury elite firewire hard drive, while typing on the keyboard and viewing the screen of the old PB. Nice! The lag time is almost imperceptible, and it's as though I still have the 17 inch PB, though it is now on its way to Apple for a repair.
I will admit, though, this screen seems kind of small...
Yeah SuperDuper!