I'm with Luke, at least chuck the blades and landboarders together in the one heap. Buggies should be separate. The way I see it, you have two classes:
1) Vehicles strapped to your butt (buggies, bikes, blowcarts(but let's not go there!).
2) Vehicles strapped to your feet (landboards, blades, dirt surfers)
(Yes I jump on the landboard too, no offence taken Luke
As for Goshen's idea of a championship / competion, sounds great. As for the height competion, I think the step ladder thing may go pair shaped or impractical. If the kiter stuffs up, then he might crash into the step ladder (ugly), the holder "upers" well they just have to watch out and get out of the road if need be. Then there is the case of, oh bugger I can't reach that high. Then there is the now did he touch that line or not? Why not the way they do it for high jumps athletics, a long bar loosely held up, so if you don't make the hight the bar falls off. It's a simple pass or fail, no questions asked. Sure we will need a longer bar (is that practical?) and the structure holding it up would have to be flexible enough so if the kiter stuffs up and hits it he/she is not going to get impaled.
Here's another thought, why not a "GKC" (Geelong Kite Club) gps that has height measurements on it. You strap it on, do your jump and then read the gps. Sounds a lot safer to me. I know the paragliding guys have meters capable of height measurement, so if the ordinary gps does not measure hieght accurately enough, this may be an option.
Well there is my brain dump.