Just a question, If I were to order from the Seymour Duncan Custom Shop and asked for them to hybrid a pickup would they only be able to do two Humbucker coils or could they use coils from a Single Coil to make a Humbucker?
Well, a humbucker relies traditionally on a bar magnet on the bottom, and a s/c has magnetic polepieces. You'd have to have the magnet for the 'humbucker' style coil one with vertical magnetic orientation (rather than horizontal as normal).
I'm sure they could tell you whether they had the bits to get this critical bit of the equation done.
If I remember correctly the old PRS Standard Treble and Bass pickups had one coil with magnetic slugs and a coil with non-magnetic screws and an Alnico Bar magnet below the coils - so it should generally be possible. Whether they sound like you want is another question.