OK, they're not tubas, but if you don't already have enough Christmas recordings please check this out.
http://cdbaby.com/cd/trombonesla" target="_blank
It's called "Carols from the Bells" and is performed by a Who's Who of L.A. studio trombonists. This recording was put together by Bill Reichenbach, who also did most of the arrangements. Perhaps the best part is that proceeds go to a foundation that helps musicians with medical expenses.
The cdbaby page has sound clips for each track. Be sure to catch "Santa Claus is Coming to Town." These are extremely creative arrangements that are wonderfully played and recorded. Buy copies for your buddies in the trombone section and an extra one for you to keep!