Yeah, you can glass it if it's not to large of a hole. There's also something called "Kitty Hair" that may work. It's like bondo with long fibers added. Sometimes it's good for building up areas.
Here's a complete rocker panel replacement that looks pretty easy.
http://www.minitruckinweb.com/tech/b..._panel_repair/
They're making their own panel but you can usually order them online really cheap.
Damn, I haven't done any restoration work in years. This is kind of giving me the fever.