doc -
You might also do a search on e-bay under Models-Automotive-NASCAR-Decals. There are usually some Kulwicki schemes on there, as he was a fairly popular driver.
Also, try these links:
http://www.venturacircuit.com/no_5_thru_10.h
http://www.racinghobbies.com/decals.html
Haven't used either company, so can't give you any specifics on quality, price, availability, etc.
HTH
lowdog