BKP responded to my inquiry about custom pickups by saying this:
Hi Uriel,
Thanks for the email but I'm afraid we don't really offer that type of service because we want to make sure 100% that any pickups we send out sound good and that we can offer a life-time warranty as well. For example, a new humbucker can take weeks and even years to design and test, before it is road-tested by artist friends and finally signed off.
We have over 20 neck models to choose from so let me know if you would like some help narrowing it down.
Kind Regards,
Ben French