I went through this exercise a few months back. Good luck finding anything by searching for LUV parts. Its just a needle in a haystack that you will find new old stock parts.
The headbolts for the LUV are socket head 12MM X 1.50 pitch X 102MM length with a 10.9 hardness. Searching for metric distributors that have this size is also heaps of fun and generally fruitless.
However, all is not lost. It turns out that Isuzu used the identical bolts in the later Trooper 2.3 liter engine, a 4ZD1 or the 2.6 4ZE1. After I found this out, I got a set off eBay searching those engine parts. They also come with new parallel ground washers which is a big plus as well. Top Line makes them and Go Engines sells them on eBay
http://cgi.ebay.com/ebaymotors/94-95-IS ... enameZWD1V