Rustoleum. You could do that, but it'll look like crap, not at all realistic, and probably wouldn't hold up well.
What with the primer , a color coat and clear coats, all that work, one would ask why not do a nice color paint job instead.
or
you could ask a plater what it would cost and do it for real. here's one in NY you could contact
http://theplatingsource.com/?gclid=CL3ItNbRysYCFdgJgQodHswFmgfind out what you need to do , and if they would want to do it, if you can afford it
or
you could plate it at home in copper, you tube has some insight on that, may be fun or a waste of time
depends, but at least these sites can answer some questions if you still want to go that route.