Jez,
I've annodized cranks, seat posts, cable hangers, stems, Ringle Bottle cages, and CK hubs.
The orange was tough as it tends to come out more "goldish" than deep orange. Even with longer cook times to build a thicker base (micros thick, mind you

) and generous dye periods the best I could do was a moderate "drank too much orange koolaid and threw up on my best white dress shirt" hue. Alot of it has to do with the type of aluminum as well as meticulous preparation.
Ended up sending a set of cranks out to have the orange done...after 5 months and countless phone calls they came back worse than my effort...ughh!
Here's a link to an excellent site for info, Ron's a peach to talk with as well...
http://www.focuser.com/atm/anodize/anodize.html
I went ahead and bought his complete book, an excellent source for the money.
Now, if you want to talk cool, I set up a TI anno line that kicks butt!
cheers,
rody