That is awesome. This pickup, assuming it works well, solves an issue I've been pondering lately - potentially just going a 1 guitar/drummer route with no bassist. And the thought in my head was exactly to double the low E and A strings so I didn't have to get a 7 or more string guitar and/or learn to play like Charlie Hunter.
I believe the guy in Local H tackled this "low 2 strings as bass" problem with a complicated signal chain, but here looks like something relatively simpler.
It's interesting that this requires a battery but isn't the conventional 9V active thing. Evidently you get to keep your other leads/pots passive, which is really nice.
I'm wondering if the optimal application is in neck position (from the looks of the demo video), or if it would work decently in bridge position. And if so, if trembucker/F-spacing would be available there.
Also, I'm curious how the actual pickup sounds, bass note capabilities aside.