Willy Hess also included an Appendix (Anhang) of Doubtful Works in his catalogue, a few of which composition have been recorded.
Hess Anh. 4 “Marsch in geschwindem tempo” for piano is performed by Steven Beck on Military Music for Piano from Monument Records. The Beck CD is available here.
Hess Anh. 8 Flute Quintet in G, arranged from Piano Sonata op. 30 nr. 3. Kontrapunkt 32160/61, Toke Lund Christianson, Flute.
Hess Anh. 21 Bagatelle “op. 119 nr.12″, is played by Steven Beck on Beethoven: Cameos for Piano, Monument Records 03.04.01. That disc is available directly from Monument Records.