The best source for Volvo sheet metal is Volvo. Use one of the Volvo suppliers
that sell OEM parts. The metal is the best. An alternative is to check out
Mill Supply. I think they are in Ohio. They sell a lot of sheet metal replacement parts.

The hidden message in what the shops are telling you is that they don't want to
do the work. It's probably for the best because it's probably too hard for
them. Any high quality body shop that really does metal work can do a fine job
of replacing your rocker panels. In my experience with 240s if you need rocker
work then your car will need floor pan work also. The pinch weld where the floor
meets the rocker can rust just inside the vertical pinch weld. This is part of
the floor. It is very true that whatever rust you see truly is only 10% of
what is there.

You may have to expand your search to be regional. Try to find
shops that do the work on Mercedes and Porsche cars. These are the quality autos
like your Volvo and these kind of shops do higher quality repairs. It might be
more money but quality counts for this kind of repair. Its a structural part of
the car. Hope this helps you. Have a happy holiday!
Dave 82 242ti 262k mi.