- "Konzertstück" (concert piece) is a common name for short musical works with one or more soloists and orchestra.
The Concert Schtick for Two Violins mit Orchestra was performed by Itzhak Perlman and Peter Schickele with the Boston Pops Orchestra. The Schickele number of 2+ is given on Wikipedia's list of P.D.Q.'s works. That article spells the title "Konzertschtick."
The score is available for rental from Theodore Presser. There it's spelled "Konzertshtick."