you can have items vacuum chromed or vacuum plated,
this includes, silver /chrome,
a warm gold kind of colour and also a brass'ish' looking finish-
this will work with any non organic material, -
the place i used was down near brighton and i gave them a call and they said as it was only 2 small peices if i dropped it in to them they would add it to the next batch of production work they were doing and it didnt cost me a cent
they specialised in lenses for torches and similar which they chromed, - its a thin coating and it can scratch if you are heavy handed but so long as you protect it or laquer it you should be ok,
may be worth looking in the phone book to see if there is anywhere local who may be able to help... they may also do a larger range of finnishes and colours/ matrials than the place i used...