Although I wasn't there, looking at the screenshots you can see that they are using a Voodoo3 ;-)
If I remember correctly they use a Prometheus... and you will be able to use current p96 drivers... I don't know how many drivers will be ppc native, I guess that the voodoo3 and permedia2... others shouldn't have so much priority. The guy that was coding the Radeon drivers posted some time ago in one of these forums that he already had WB running with his drivers...
About the software they ran, at least we know that they showed native OS4 apps (look at the fractal program)
Most of this is pure guessing, but it would be nice if someone who was in the show did a small report for us ;-D
@Thomas:
I hope you'll update the datatype/codec system soon so we don't have to rely on third party viewers and players...