Call for Artists, Making Money at Juried Art Fairs, Craft Shows and Festivals
Sometimes I play a game of trying to find things on the Internet. Didn't find the ProPanels but this was interesting.
Ernie mentioned his DIY plans on this thread: https://www.artfairinsiders.com/forum/topics/diy-panel-system-semip...
There are also numerous, similar things on Pinterest.
Best of luck!