I was leaning towards the het hypo explanation but wasn't sure if it would wipe out the vanilla head spot so much. Just to throw another monkey wrench in, here's a picture of the sire with a pinstripe...
Definitely the brightest vanilla I've seen, and the breeder that produced him doesn't have any hypos in his collection that he knows of... You can see he's just as bright as the girl in question, but has that distinctive head spot vanillas are known for.
That's the girl, and she's staying right here also.Both yellow bellies were smokers though, they came from a Barnhart line black pastel yellow belly.