Go for something that can be built with easy to get (= low price or sponsoring) materials from the modelcar or DIY shop. No spinners but promote other moving (and show-)weapons if possible. Maybe a minimum part of the total weight for sacrificial props. Something that doesn´t need a lot of arena space (play at schools) but can still be seen by an audience at fairs.
I would go for 3 classes: Raptors(*) for entrance level and fun, the current feathers to step up a bit and have fun, heavies as top show monsters to have the ultimate fun.

*) Raptors are a ready 6 kg class, populair in Germany and Scandinavia.

(Message edited by mjm on October 14, 2005)