So, here's the demo.
It's ready to use for whatever you want. If you think about it, the code behind TwirlyMol can easily be adapted to displaying other types of 3D data, for example principal components graphs. What else would be useful? That's up to your imagination (comments below welcome).
(1) Colours of atoms taken from the Blue Obelisk Data Repository. Even if you don't understand what the Blue Obelisk is about, I'm sure you can appreciate the benefit of shared chemical resources like these data.
(2) IE performance is still much slower than Firefox, but is better than with Twistymol.
(3) With Firefox, adding a large number of SVG molecules to a page is much slower than with Canvas. If doing this in practice, you'll need to add them in chunks of 50 or so, with a setTimeout() to add the next 50.
(5) If you use mouse gestures, rotating or zooming with the right mouse button can trigger a gesture event. One way around this would be to implement support for modifier keys so that shift+left button causes right button behaviour, while alt+left would cause middle button behaviour. This would be quite easy as the dojox.gjx library has a function for testing whether shift is held down (I can't remember about the alt).