Thanks for your feedback, I passed it on during the presentations.
The president of mobile for NVidia, acting on behalf of the Kronos group, said basicly the same thing as well, - essentialy xml based formats (including their own Collada format) are good for storage/creation but not for delivery.
However, it seems that X3D format might well fit the bill despite that. It seems a rather flexible 3d format with a lot of support, but also a binary variation as well (which isn't used much yet, but for the mobile market that might just be perfect).
http://en.wikipedia.org/wiki/X3D Discusions are still going, but it seems this might be the top contender at the moment.
If you get a chance to check it out, be sure to let me know as there is still very little feedback from actual 3d mobile coders on this issue.