Warwick Thumb bass. That guy looooves to be horizontal. Had to sell mine, the neck dive plus the long reach was killing me. Ended up selling it to a tall guy with long arms who loved it.
I'm with the OP and mjac28 on this one. I own 2 Thumbs, notorious for "neck dive" and I've never had a problem balancing the bass while I play. The NT Thumb 6 is very heavy, at a fat 'n sassy 12 lbs, but I've never had problems with the neck being elsewhere than in my hands on either guitar. Maybe height and length of arms has something to do with that as I'm 6'7".