I'm not the seller of this catalog, but check out the double tuba being played by Bill Bell. Has anyone every seen one of these or heard of this. It looks like an interesting concept, although I would think not too practical. http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 26419&rd=1
That is the famous Bellophone. As the ad says, it is a combination BB-flat tuba and baritone. It was a one-off made for Bell. By several reports not a great instrument but an interesting piece of tuba history.