Re: How hard is it to CNC this?
 

you can actually do it on a vertical mill if you have the 1/8th inch long endmill. But you must lathe it down first and then put it in an indexing head. Then if you have the time you can rotate the piece while lowering the endmill after each rotation. Then make all the other cuts you must.

Re: How hard is it to CNC this?
 

Another option would be to make it in seven pieces instead of one. I would make the "orange wedges" seperate pieces that attach to the hub with machine screws - 10-32, perhaps.