DIY anodizing
Depending on the prices you find, it might be more cost effective to do it yourself. I've anodized a number of parts, all colored, myself. I don't have the details here at work, but if you're interested let me know and I'll dig them up at home. If you already have a constant voltage power supply, you should be able to get set up for under $100 and that will let you do whatever small parts you wish.