Saw this new spinner just posted on the morris-hobby site in Japan.
3D printed, 2 piece ventilated, no aluminum backplate, 82mm
It says 'rough finish' which I guess is typical for 3D printers?

http://www.morris-hobby.jp/50_1148.html

Expensive for a plastic spinner.

We should just print them ourselves. I will be doing one before too long. Just need to come up with a clever design:-)
Google turned up a few but not with through spinner cooling.