How about hinge it on one side ( all kinds of options for that. you can have them hidden or exposed) and then put a latch system like that used on fuel doors (completely hidden)
The latch system I'm using on my fuel door came out of a Cadillac and has options to use push button or pull cord to activate it. I was using them for a latch system on the rear louvers. It worked pretty good.
Then use a spring or spring metal (like used on the fuel door) to add just a little preload to the cover so it wont rattle around. That would also help pop the cover up a little when the release latch is activated.