Blue eyed goldfish (Shubunkin), common or rare?

[wataugachicken]

that is a very nice looking fish. good luck with him, he'll be really incredible when full sized.

 

[Flaringshutter]

Blue eyes aren't unheard of for shubunkins, but they're certainly not very common. I have seen it in many half-breeds, where a solid color comet has crossed with a shubunkin. One of my juvies resulted from just that combination, and he has one blue eye.
Your fish is gorgeous!
Breeders (like David!) are a great place to get shubunkins. You can also try goldfishconnection.com, raingarden.us, goldfishnet.com, and aquabid.com.