I have, the cover/small awning that goes on the drivers side of a Jayco caravan.
When I sold our van a year ago, some how, it missed out on going to the new owner, who I no longer have a contact for as he moved after he bought the van.
From memory, its never been used and I think it went into a slide on the van and gave some shade/shelter from the heat.
I think our Jayco was about 18 feet long? It was a 2004 model, but i'm sure it would still fit a mountain of other years as well.
If no-one wants it, I might stick it on Gumtree for a $80.00 in January.