Finally, the old site was starting to look a little tired...
But, with the update they now have wallpapers available of there (HSV Only) entire build history. From the VL Walkinshaw right through to the latest E Series Maloo R8. Mostly only 1024x768 but some slightly larger 1280x1024.
Check it out here:
Holden Special Vehicles - Build your HSV
Although the only notable exception I came across was the VT II GTS 300.
Does anyone have any good pics of this, the only decent one i have is this: