I have powder coated bolts on a bike. In the picture below the caliper,disc and a few bolts are done in black, the front forks, caliper bolts were polished then coated clear and the bolts holding the disc to the wheel are done in almost chrome. You will want to bead blast the bolt then tape off the threads. It works well for bolts you don't remove often but will never take repeated removal and forget the ones you want to use an impact on.
http://home.comcast.net/~rthompkins/IMG_0123.JPG