Here's a couple of options...
Badger Plating Inc (Warning, I guess Badger Plating it pricey from what I've read.)
(414) 482-4820 4021 S Kinnickinnic Ave
Milwaukee, WI
epi.com (Give these guys a try. I'd be curious to see what they charge because I want to get my chrome racing mirror replated, too.)
Electrochemical Products, Inc.
17000 West Lincoln Avenue
New Berlin, WI 53151-2781
Phone Number: 262-786-9330
Fax Number: 262-786-9403
Hope this helps you some.