Place a want-ad on craigslist for one already done....you might get lucky.
Try a local chrome shop, they usually have metal finishers that can bring them back to life. Bumper Boyz has a good selection but their quality is so-so.
Those older bumpers are really thick which makes them fairly easy for a guy with a torch, anvil, grinder and BFH (big hammer). It helps to have someone holding the 'dumb' end too
I've repaired many in the past but I paint them if their mine.
Bumper Boyz have been around for a long time. Have heard good/bad things about them but if you need one they would be worth checking out. They hit some of the big national meets so if nearby you can sve on shipping. I have had luck on e-bay.
I don't know of anyone that has ever been completely satisfied with chrome replating. And now that the industry has gone to plastic many of the shops that once were, are no more. I suppose it's becoming a lost art. The world needs a little more chrome.
There are re-chrome shops out there. You have to do some searching. To find really good one, you have to search really hard. In regard to Bumper Boyz, I am familiar with their work. If you need a Bumper, they will probably have one in stock. You will get a driver quality bumper. The difference is in the final buff that they use. Their final buff is a show quality shops inital buff. When it comes to chrome, as with most anything else, you get what you pay for.