I think you can powdercoat almost anything...the question is weather it will adhere to the surface well.
When you powdercoat somehting you spray on an electrotstatically charged ..um..well..powder. then you het it to a curing temp. the powder basically melts and then cures kinda like an enamel paint. They make translucent, florecent (sp), metallic, chameleon powdercoats...It's a straightforward process and reasonably easy if you have a dust free place to spray the parts.
There are some challenges applying heat tho...what it if you want to do a whole frame...you can cure it in sections with an infrared lamp, but it'll take you a while (like 30-45 mins a section) or you could have a big oven (read big $$$). But you can do little pieces in a toaster over...of course it wouldn't be much good for toast after that.
Not to take away from the people that do it...there is an investment in equipment, but a starter spraying setup is less thtn $200 bucks. But then you need powder, a place to cure it, a compressor and other littel odds and ends. So, if you want to change the color of your bar ends...this probably isnt and economical do it yourself thing. If you want ot do a whole bike, or start a business...that's another story.