There's a number of forumites who suspect that the PATB-1b started as a Parallel Axis version of the Custom 5. I wonder how different that'll wind up from a PATB-1b with a ceramic magnet.
Very curious how it turns out, as I always am with anything Parallel Axis!
I had a PATB-2/PATB-1n set installed on a guitar around 2003, and there was no Custom 5 in the Duncan catalogue back then. Users may have already been modding the Custom at the time, but it wasn't an official offering.