Beautiful! I have been thinking that I'd love the HD650s a bit more if they were a little more aesthetically interesting... but I'm also REALLY hesitant to actually: 1) potentially screw them up, 2) destroy the resale potential (just in case), 3) lose the sennheiser logo.
For the curious: how did you do the paintjob? Just remove the grills and spraypaint? Did you prime them, use a certain kind of spraypaint, strip the original finish first, etc.?
I'm not experienced with craft/hobby paints/lacquers, so I don't see myself following suit anytime soon. But maybe someday!