Thanks for the detailed reply. I never even thought of spray paint, but it's a great idea.
I don't know what the band is made out if - and the orthodist isn't saying except that it's a special resin that's been developed for maximum biocompatibility blah blah medical jargon. There is a PDF with some tips that specifically mention acrylics and watercolors. http://www.cranialtech.com/images/st...tsdecorate.pdf
As for lettering, I was thinking of using stencils to paint them on. Seems too intricate for decals or cutting...
But the stripe and arrowhead (and maybe a ship on the back) will definitely be decals. Do you know any companies that print good, thick, decals? I've googled a few but am not sold on any yet.