you might be able to get someone to waterjet or plasma cut those for a reasonable price.
but to machine those with conventional (or even CNC) machines will take a big machine; and time on those doesn't come cheap. if you can supply the program, it'll be a little cheaper, but the guys that own the machine will still want to charge you to check your code before they run it. . . . downtime and repairs on those suckers is a killer for jobshops trying to compete with the far east.
maybe check the kind of shop that does custom wheel fab? the machines that make 22" billet wheels could knock those rotors out pretty fast.
I could probably manage to cut the OD with the manual equipment available to me, but those cutouts would be a pain. (extra setups) Round cutouts would be simpler to cut on a manual machine.
yours are pretty, though. . .
(7/16 / 11mm seems a little thin for a disk thats going to be carrying a heavy axial load at the rim . . .)