Hi Tom. Great thread. I am waiting to listen to the (sonic) results when the bass materializes.
I had discussed the exact idea you are describing with one of my favorite luthiers (Sheldon something was his name

) few years back. The idea was to have P, reverse P, front J, back J (side by side coils) from the 4 coil cluster and then on top of that parallel and series of the above combinations!!!! To make things even worse, I was talking about a 2 cluster bass with the usual 4 pos selector to control the neck/series/parallel/brigde clusters!!! Each cluster would look as a normal soapbar pickup. The problem was that it would be too complicated to achieve all of the above combinations in an easy and orderly fashion. So the idea went into hybernation (until I think of a hidden way to access all combinations

).
I am really happy that you are making it come true. Let us all know how it goes