I've got a friend who has inherited a 1878 colt frontier that is rusted open. He needs someone to restore this old piece. Anybody know of a good smith who does restoration work like this??

I don't know that particular model, but probably the best place to start (and best place to have it done if he does that model of revolver) is Doug Turnbull of Turnbull Restorations.

Red

Bill Adair is another, he specialises in old guns. He is also reasonably priced.

+1 for Turnbull restorations.

It really depends on how much money you are willing to spend.
For example, i am restoring a WWI Colt 1911 for a guy right now and with the markings recut, polish, and all external parts replaced with Wilson Combat parts, includuing fitting is going to run about $750-1000.

Give a price range.

-Spencer