Jared, I found this thread on the nc4x4 board and posted up about your trooper. The kid hasnt gotten back to me if he is interested in yours or not yet but here is the thread if you would like to make an offer or see what he says. I will post anything ya need or offers you wanna make to him. And I am looking for someone to buy the runner too, cause its not looking good for me at all.
as far as replacement parts go, you can get anything you need from parts stores like Advance. There is growing support for aftermarket parts as well. ARB makes lockers for both axles. There are suspension kits and body lift kits out there. These truck come from the factory with 4.56 gears and 4 wheel disc brakes. A set of lockers and some bigger tires is all it would need to be a decent rock crawler. independent4x4.com deals with a lot of isuzu stuff and would probably be your best source for aftermarket parts since they are located in richmond.