A bit of a bump but...
You guys should checkout the latest development on the SIO2 Engine (
http://sio2interactive.com), version 1.5 is about to be released and there's alot of features added on top of the 20% faster boost.
As a sneak peak of what can be done:
SIO2 Custom Lighting, Physic Constraints, Toon Shader etc...
And alot more to come
Cheers