Crookshanks is not a "dollface" Persian. he's a regular Persian.
Snowbell is a Silver Persian.http://www.cfainc.org/breeds/profiles/persian-silver.html
http://www.cfainc.org/breeds/profiles/articles/persian-silver.html
They have bred for colour and were not crossing out to more extremely flat faced Persians in other colours. so they have been slower to change to that style and they tend to be a bit less extreme in type. So you don't have to look for someone advertising "dollface" Just look for Persian breeders -- either Silver Persian or "Chinchilla Silver Persian"
Or you can get a Solid White Persian with a face more like Crookshanks,
The cost will probably start around $600 for pet quality. It's really difficult to impossible to breed and raise quality pedigreed cats, take good care of them, do the necessary health testing, have them altered and shots before placement and keep them up to at least 12 weeks, and sell them for less.
If you're in the US, registration should be with CFA Cat Fanciers Association), TICA, (The International Cat Association) ACFA (American Cat Fanciers Association), or there are a few small ones CFF,AACE, UFO. . But really they would probably be registered with at least one of the first 3.
You REALLY want to make sure the breeder is testing for PKD and the breeding cats are PKD negative PKD is a very serious disease that some Persians are at higher risk for.