I just found this when doing a search on other things.
I have a B2V. The pickups are 7 string guitar HB size EMG HZ's. The only thing I can find that will fit stock and may work OK is the Dimarzio X2N7 or the Q-Tuner GL7. The X2N's are good in the B2ADB, so the -7's may be good here. Lots of people like the Q-Tuners here and I see no reason why the guitar one's aren't suitable. But they are expensive.
http://www.q-tuner.com/gl7.shtml
Villex may be able to pot his pickups into a HB7 shaped casing, but you'd need to email and ask.
Alternatively, you could have the routs enlarged slightly for the EMG40 size which will give a much broader range of BG pickups.