A Festival of Compositions for Conductors

Composers are always being commissioned to write pieces for particular orchestras, opera companies or soloists. Why doesn't someone commission a composer to write a work specially for a particular conductor?

I'm not talking about works that feature the conductor as a "soloist" in any overt sort of way, as in John Oswald's Concerto for Conductor and Orchestra or Dieter Schnebel's theatrical piece for solo conductor, Nostalgie (Modelle No. 1.) I mean, a composer writing a work for full symphony orchestra with the particular personality and style of the person on the podium as the force that underpins and shapes the work.

There are so many charismatic conductors working today with strong, individual styles that would doubtless inspire great or at least interesting compositions. How about a festival dedicated to commissioning and premiering a few such works, in which one orchestra performs pieces written specifically for the likes of Gustavo Dudamel, Alan Gilbert or Marin Alsop?