Looks nice, I like the hinge idea. I've been meaning to do something like that because my tire cover sucks, I'm not sure its for the right car. It's too small and its the wrong shape so it slides around all the time.
a guy I know cut some plexi glass like that and glued his carpet to it, worked pretty good, carpet doesn't slide around when things are on it anymore either. His basically looks like a piece of hard carpet.