Sherman's (Detroit) or Cross Canada Auto Body (Windor, ON) may be able to provide you with aftermarket panels.
FYI - Most of the aftermarket panels are stamped in Taiwan or China so the quality is questionable at best. I know because I'm living the nightmare right now.
If you want good replacement panels I suggest you try to find rust free used pieces that were removed from the donor car properly. There are several SW or high desert used body parts suppliers. eg. High Desert Mopars I've bought fenders from Jim and they were perfect!
The more visible used parts people advertise in magazines such as the Mopar Collector's Guild magazine.