I take it you've tried Gil_m?
If you are at a loss, I work for a sign manufacturer, and have made enquiries about this before (my bike is post "retro" and wasnt in the catalogue, so Gil doesn't have my decals).
Basically, with a good enough image, I can get the graphic guys to make the image, then get it printed onto sticky vinyl
Let me know, and I will have a word when I get back after New Year
G