John,
I live in NE Ohio and use Paul's Chrome in the Cranberry area of PA -
They are the best on pot metal that I have found, but not cheap.
Paul's Chrome
90 Pattison St.
Evans City, PA 16033
800-245-8679
I was at Paul's yesterday and they are running about 8-12 weeks. Keystone is probably a little longer. At this time of year, they get a "rush".
For bumpers (not pot metal) several of my friends recommend Keystone Plating.
Keystone Plating
PO Box 7667
Akron, OH 44306
216-398-7788 (They will usually quote on bumpers by phone if you describe accurately)
Fred