Looks very cool! Getting better and better!
The Speed Hazer’s solid volume rendering (voxels if you will) actually isn’t “broken” as I’ve noticed, only that it previously had to overcome a limitation that is gone now and I didn’t update that “work around”. So in the next revision it’ll be all super-peachy again! 
You could already play with the solid rendering, but I’ve also renamed two inputs to make it more clear in the upcoming version! (value = density, density = global density). It currently only renders against objects or ground and not the background, but the upcoming version renders against empty backgrounds as well… …just like it should’ve.
I’l try and play around with it over the next few days.
No doubt user error on my behalf somewhere, but I’ll post a few images shortly anyway.

