I did mine a few years ago, looks great, but be very careful round the retainer pin, as if you paint that in place it makes it very hard to get it out when you need to change the pads. If the pin brakes its a pain in the arse to have to drill it out.
All the official caliper paint kits cost about £20, but I've just done mine with silver engine laquer, only £5.99 from a motorspares shop. Can't see why you'd need the pricy version, unless it really does get that much hotter than the engine.
Make sure you wire brush all the surface gunk and rust of the drum before you paint it too.
The rust will cause the paint to bubble then flake off if you done get rid