Genetically speaking you can mix a pied with any type of morph; however, keep in mind a pied is a simple ressisive so when breeding a pied to anything is going to give you hets unless the pied gene is in both parents. Now with this said to get a double resessive you will have to breed het to het, which means you normally have a 1/16 odd of hitting the double combination. For example the Pied Clown just produced this month by the snake keeper. If you breed a pied to a domin gene it is just easier to get a double combination morph, of the top of my head I beleive if you breed the het back to the pied you should have a 1/4 odds of getting what you want.
Personally I at head patterns when thinking what I would want to make into a form of pied because pieds always have a normal head pattern for the morph (for example the head pattern on the pied clown looks like a normal clown) and then the bloches of white will very.
I hope this helps,
matt