Much as it'll never happen in my lifetime, I'd love to be part of an areas (or any other contest for that matter) where every piece was brand new for the day.
Maybe even do it with no CD recordings available beforehand, and agreements a-la music for battle creek to prevent public performance, so as to ensure as many different interpretations as possible.
Forget winning and losing, what a great musical experience that would be!
Probably the only way it'd happen would be to use complete (or almost complete) unknowns. It'd be prohibitively expensive to commission new works at full rates from established composers. It'd would be a good day musically though.
The CD is a bit of a cash cow to an extent I guess - especially if you reuse recordings previously issued (which I don't know if it's the case or not), although the idea of downloads could potentially do away with these things in the fullness of time.
AFAIK there was always an embargo on public performances of new commissions on test pieces which - again as far as I can remember - also included 'open rehearsals'.