I've recently come across Unity3D - a 3d games development kit that outputs to browser and is free if you're not a big company. I think for people that know scripting it would be relatively easy. The intro tutorial has a little animated alien character wandering around collecting things. It's very impressive. Easy to embed as well. You do need the plugin to see it, but it's not massive. I look forward to playing more with this. Sadly no Linux port yet for the plugin. http://unity3d.com/