Sorry to bump my own last post, but I did a little optimization and the whole thing is now about 15-17 times faster (heh). For smaller things realtime raytraced light is fairly viable. It's still the same example, same keys and all that.
I'm fairly sure there's more to be squeezed out, but for now you get the latest example. Touch a light to start. It also doesn't render unless necessary now, so don't get too excited by the thousands of fps it shows while idle.