I was listening to one of Johann Georg Albrechtsberger's concerti for Jew's Harp, Mandora, and Orchestra (no, really-- http://www.arkivmusic.com/classical/Drilldown?name_id1=127441&name_role1=1&bcorder=1&comp_id=5490 ; I believe he wrote seven, of which two have been recorded), and started to wonder what other, shall we say, unusual instruments have had genuine concerti written for them. There are several -- well, at least a few-- harmonica concerti, accordion concerti, and even theremin concerti. But how about really atypical solo instruments? I do mean serious concerti, not gag pieces or new-agey slush such as pan pipe 'concerti'. Any suggestions?