I understand not wanting to exclude people, but if it is a Bryce oriented challenge, how are you excluding people by asking them to make heavy use of the program that the contest is based on? Are you a Bryce guru if you can make a terrific render of objects and textures you created in other programs?

It is a bit hard not having access to, much less any skill in other software that might allow me (or others) to make a better creation than what I can do with just B4.

On the other hand, my artist skills aren't up (yet) to recreating what my imagination comes up with in any medium, so pure Bryce or not, I'm not up for a guru title any time soon.