It would be quite difficult to hold a track design comp, without the tools to do so.
Unless the tracks were just visuals, drawings, a layout, sketch, 3dsmx Scene, and then the winner worked closely with the Devs in realising the finished track.
It wont happen at this stage I dont think - There are no plans to release the track editing/designing applications - and there would be far to much work involved in realsing the finished atrical.
Im not saying that it cant happen - just saying not yet - one day after S3.
In my opinion of course - The Devs may suprise us, but I doubt it...
Improved AI next..... ya ya