There's definitely limited parts, but usually can still find stuff. Two main sources are
1) isuzupartscenter.com....CALL and ask for Scott in Parts.
2) Jerry Lemond was the master training mechanic for all of Isuzu US, when Isuzu left the US, he bought like a huge barn full of New and used parts. His email is jlemond@bellsouth.net. He's an older man with bad eyesight, so write everything in ALL CAPS. He uses PayPal to get paid. Tell him the "Isuzu gang" on FaceBook referred you.

FYI...there's more activity on the Vehicross FaceBook page. However, it doesn't have the huge amount of reference material the .info site has.