Aluminess is the way to go (I have to admit bias as they do a phenomenal job supporting the forum: viewtopic.php?f=25&t=4898
Reunel are an option for a different look, the height of the van should help as much as anything since they don't have the tubes wrapping over the lights. Search Jeffery to pictures of his van with them, and then Myriadmyriad has something that looks like a tube baja deal, but I can't remember the brand.
Not sure if any of them fit Chevy, but that's a good looking van. A nice offroad bumper wouldn't hurt though!