Fairly certain it's done using mayavi - http://docs.enthought.com/mayavi/mayavi/index.html

This looks something I've been looking for. Are there some products (commercial sw, or libraries) in this space?

I'm unsure about the commercial licensing aspect of it if that's what you're asking, but mayavi has both a GUI interface as well as a scripting interface depending on how you want to use it. In my experience it's essentially the library to use for 3D plotting when matplotlib isn't cutting it.

(I just checked wikipedia and it seems it's released under BSD license. Unsure if other products available which are built on top of it)

Some 3d software like blender maybe?

http://blender.org/

Don't know why you were downvoted. Doing e.g. dataset -> .vtk file -> ParaView to add whatever vectors, color maps, surfaces etc. you want -> .obj file -> Blender to do final lighting, coloring and raytrace isn't unheard of. I've seen it done several times in CFD, and I've done it myself.

It becomes a bit of a pain for animating datasets, since you need to do Blender scripting with Python which is far from intuitive. But it's doable.

Having said that, this doesn't look like Blender.

ParaView would be a possibility. Many tools can export VTK files for it.