OffsetGuitars.com

Well I finally got what I need to start producing these pickups. 
One very important note here is the Mustang Bass covers are slightly smaller than the XII see picture below.
The thing is there is enough space that I can make a XII that will fit the Mustang cover.  I will make a pattern for both.

Mustang Bass top / XII bottom.

Thanks for the update.

It's interesting those covers are different...  I would have bet they were the same.

when you think about the space it takes for 12 strings and how thin a mustang neck is it kinda make sense.