Piano Concerto No. 8 by Daniel Steibelt
Sadly, this appears to be lost, but hopefully it will turn up in some archive one day.
There are a few others not mentioned.
Arthur Bliss - Bazara: With mens voices ad lib.
Alan Bush - Concerto for piano & orchestra with solo baritone and male choir (stupidly long and horrid)
Pierre Capdevielle - Concerto for prepared piano, celesta, electronic organ and vocal ensemble (avant garde crap).
Giorgio Ghedini - Concerto dell'albatro for piano, cello, narrator and orchestra. The narrator reads out sections of Moby dick. (I like this, recording on you tube).
Eugene Hemmer - The voice of the Grand Piano for narrator, piano & orchestra.
Andrzej Hundziak - Concertino for piano, childrens percussion & 3 part childrens or female chorus.
Danilo Lorenzini - Concerto for piano & orchestra with one soprano voice.
Maurice Ohana - Tombeau de Claude Debussy for piano, soprano, zither and chamber orchestra.
Peter Schickele - Three Girls, Three Women for male sining pianist and orchestra.
Leo Sowerby - Concerto for piano & orchestra with a soprano obbligato.
Joseph Tal - Concerto III for piano & orchestra and tenor voice.
Alexander Plinkovsky - Concerto for piano, banjo, microwave background radiation and mute castrated choir.