This is a listing for Alembic electronics without the pickups.  I've never heard of an Alembic push-button 3 pickup selector.  Did they ever produce such a beast?
 
Bill, tgo

Interesting indeed, looks like it could have been done by Alembic (though you would also expect a connector for the output on the switching board)

Coincidentally, the same seller has 3 Alembic pickups listed separately. Interesting find.

3 pickups?! Coincidence?!?...... Pshhh... Thats just swamp gas!