Yes, the Isuzu diesels have a pump mounted to the back of the alternator sharing the alternator shaft.

The 1989 Trooper sounds like a great candidate for a conversion. I believe it has the same frame as my truck, so the easiest route might be to do what I am doing and import a 4JB1-T with transmission and bolt it in. You'll still need to modify the fuel, electrical, power steering, etc. systems, but you'd have to do that no matter which engine you chose. Driveshafts need to be modified, too, going this route, but I think that's easier than building motor mounts.

Keep us posted and feel free to ask any questions you might have.