Bill Holland is a high-end custom builder in Southern California. He custom builds the old-fashion way: one at a time by hand. Joe Bell has been his painter since the 80's. He's currently considered one of the best Ti builders that you'll find; again, all done by hand.
However, like a lot of custom builders who will build you a tandem, it's not his speciality so the tubing is probably not highly refined / custom drawn for the application. Regardless, it looks like a great frame. I may even bid on that one...
Perhaps someone with first hand experience will chime in...
Bill Holland Cycles, Inc.
3735 Kenora Dr., Suite B,
Spring Valley, CA 92116;