Planet Waves HDMI Locking Clip
This product is pure genius! Although it is shown being used as a method of securely connecting two HDMI cables together insuring they will not 'accidentally' become disconnected, I believe one end of the clip can secure the connector to the rear of my A/V Receiver. The cable I have sometimes likes to fall out, usually in the middle of a great scene. This appears to be the solution to my (& your?) problem. There is only one small issue, it has been discontinued and is not available.
Pros: Looks like the solution for World peace!
Cons: It is NOT available!