I've recently come across an amazing instrument, while I was looking for a new trumpet - thanks to the jazz band war of 2010, I'd rather not talk about. Anyway! This instrument is called a "jazzophone", and there's very few people who actually make it. It appears to have an extra valve to block the sound of one bell and into the sound with the harmon mute in it, but I'm not entirely sure.

They run for about $5000 because they'd have to be custom-made.

http://www.horncollector.com/Trumpets/Trumpets - Piston/Sax Shaped Trumpets/Jazzophone/Jazzaphon 3.jpg