I wonder, if to save on render time, the Wave object wouldn’t serve better as the light source rather than as a volume. I like the finished result but see an Emit with Gradient Texture mapped through the Z-axis casting an equally lustrous luster. I’ll play with this soon as I’m’ near a different computer.
I thought of doing something like that soon after I posted! The only reason I did it this way in the first place was because I was interested in doing this based on real life clouds, and imitating that as closely as I could. As well as a gradient texture input to the emit, you could even do some interesting realtime object mapping of a texture onto something animated with shapekeys… deserves investigating! Hope to see something from you!