I was just wondering. This topic came up between me and my friend, and I wanted to know if there were any Trumpet-Bassoon duets out in the wonderful world of music. Either that, or a trumpet-tenor sax duet.

Well, you can take any trumpet dure & turn that into a Trumpet-Tenor Sax duet considering both are in key of Bb...can't help you w/ Bassoon tho. Sorry.
-Chris