Heat resistant paint for barbecues will work, but I've only seen it in black. I used a can of the Rustoleum stuff for my mufflers (which are big and silver and visible from behind, which looked hideous).

Hmmm, guess it is available in three colors, aged copper, black and brown.

http://www.amazon.com/Rust-Oleum-241169-...2786&sr=8-3

That is the stuff, but I picked it up from Home Depot. Any home improvement shop should have it.