To answer the question.. hmmm.. I don't know if you wanna count the time the paint took to cure or not. As for actual work put in, I would guess the Saturn case took about 2-3 hours. The Dreamcast case was a whole other monster. I messed up and started over again on the Sonic applique. I'm guessing that one took about 6-7 hours, and most of that was not painting.
Oh yeah.. the buttons. Well, when I took the picture I hadn't put everything back together yet. The buttons are still their original shade 'o gray. If I'm feeling adventurous I might change the LED from it's lovely orange to this nice blue one I got out of one of those cheapo keychains. But I think I'll leave that to people who are far more skilled at those sorts of things than I am.