Eric Vaughn is the go-to guy for aluminum wheel widening and narrowing. Here's some helpful links if you're thinking about having your wheels modified:

This is Eric Vaughn's own website. He doesn't do steel wheels by the way.
www.ericvaughnmachine.com

People really dig Eric's work on this Corvette forum. One guy said Eric Vaughn Machine is "One of the premier wheel machine shops in the country... (there's only like 4-5 really good ones in the country)."
www.forums.corvetteforum.com

These Real Rodders Wheels guys are very cool. And they like Eric, which makes them even cooler.
www.realrodderswheels.com

This website for Cadillac owners has a bunch of photos of Vaughn's work.
www.cadillacforums.com

These Jalopy guys are an interesting bunch. But they know wheels!
www.jalopyjournal.com

Here's a neat site. It's got an article written by Eric Vaughn about the early days of being a gearhead.
www.benchrace.com

Vaughn did the wheels for the '76 Camaro in the
Transformers movie.
www.edmunds.com