i find o3d interesting. if o3d turns out to be a success then there for sure will be many open source engines for it.

o3d has no specific formats. you could write loaders for every format you want. there also are very good javascript obfuscators which make the source code useless.

the biggest problem i see is that o3d is just for graphics. what about collision detection, physics and sound? i don't think good solutions for that can be done with pure javascript?