It's T-6060 Aluminum, machine polish.
I'm in good with the machine shop (personal friends) so they made it for me as a gift. If I had to guess, I doubt it cost him toooo much to make, less than $100 for sure.
They also made me a stainless steel outer ring that I designed, but my math was fuzzy so it didn't work as I'd hoped. I'll probably end up paying them for fixing that mistake.
I got the concept from a company called TTweights, they've got a website (ttweights.com i think). They make some REALLY nice looking stuff, but it's pricy.
If you want, I can ask the guy I know how much he wants for a few more if there's interest inside the group. I don't want to go too far with this though because I feel bad about reengineering TTweights' idea. I didn't steal their design by any means (I had to figure out the sizing and the visual style and all myself), but I definately got the idea to do it from them.