I don't blame you, I've become a real fan of Jonathan's playing over the last couple of years and think he's a real hidden gem of the bass world! Jonathan's BBs are indeed passive he has a pair of BB3000S (V-V-T control layout instead of the V-T-Pickup selector) and he strings one with flats, the other with rounds. I've been looking for one for a while but people that have them are keeping hold of them, and the one example I did find was both the wrong side of the Atlantic and out of my price range.
One option I'm exploring as an alternative is the BBX, these were apparently Japan only basses but they have the same overall spec and control layout, the big difference being that they are bolt on rather than thru-neck.