It's a lot of work painting a case, what with preparation, cost of paint,primer,etc, & then overall finish.
I decide to have my CM690 powder coated, worked out slightly cheaper, & finish was far better than what I could have achieved myself, plus powder coating is harder wearing, it's available in thousands of colours & various finishes.
See this thread. http://forums.overclockers.co.uk/showthread.php?t=18453248
Personally id go for the powdercoating option. Far less hassle, and as the case will be taken apart and then reassembled for you. You have the option of multiple colour choices on separate parts. I wouldnt fancy trying to de rivet a case then put it back together myself.
Ive also got a case that ive been meaning to get done. Lian Li A70F full tower. Gotta wait till i can afford it though as ill have to send it away. Was looking at a blue and black contrasting colour scheme, internals only.