Wow thanks to another board today I discovered this website
http://www.worth1000.com/
You can quickly check here all their present and past PS contests
on this page
There are some incredibly skilled artists there!
I loved the
alternate materials 2 and the
Bizarrchiterture one.. there was also a supercool one with underwater worlds but can't find it anymore LOL!
Edit - here is the
waterworlds contest