I don't know where you can get skimmer box covers, but there is a product I'm currently experimenting with called "Rock on a Roll".

I'm making a rock floating island. I'll post pictures when I'm done.

Here is a link that might be useful: Rock on a Roll

that looks interesting i wonder how it would look as a skimmer cover in reality.

It looks pretty good in their pictures. I guess we'll just have to wait to see how my floating rock island looks. I'll be covering it today. I made the form yesterday and let the glue dry overnight. I'm using silicone glue.

cant wait to see it,

you could go to the garden center or to a stone center,and get a thin piece of slate or flat rock.

pashta what ever happened with this?