Hi Neil:

Have you checked into really thin (1/32") plastics? A lot of glass shops sell these. Of course, there's always plastic laminate, glued down with contact cement, but you'll need a flush trimming router for that job. Super durable though.

For fabrics I use in picture framing, I use a modified PVA glue. Very similar to Elmers white glue, but pH neutral. You could slightly thin out some Elmers white glue and roll it on with a foam roller. This has enough tack that it will grab hold of pretty much anything you put on there. There's quite a few outdoor fabrics that would work super well as shelf liners, although this may be overkill.

Any of the products I mentioned would probably outlive your van. You want good or cheap? I hate contact paper, although I've used some rubberized mesh like material that doesn't require any glue and keeps things from sliding. I got the mesh at the supermarket--it was mixed in with the contact paper.  That would probably work too. Not sure how much time and effort you want to put into this. Actually quite a few options... I believe that Go Westy sells the original vinyl covered fabric as well, if you want to keep the stock look. Heck, it lasted 20 years after all...

Troy