WG, not sure what part of the head lamp assembly you are needing, but that price seemed rediculous to me. I went to isuzuparts.com and did the drill down and found that the right or left head lamp assemblies are $276.95. Seems a far cry from what they are asking. Here was my drill down:

input 2001 Isuzu Vehicross in the "BODY PARTS" box (box b)

then follow this pattern:
Front lamps >> Headlamp Components >> Headlamp Assembly

From there you can drill down further to the specific components you need, including the seal ($16.67)

GL man!