Design Disease launched a Wordpress Premium Themes marketplace, which you can buy and sell your premium themes there.

The site just launched and there are totally 7 themes that you can buy there. The site provides a very detail description for each themes and you can try run them before buy. Among the seven themes, i personally like Perfection very much and it is the featured theme now.

This site has a very attractive affiliate program which you can earn up to 40% for every referrer that buy their themes. Besides this, you are able to submit your themes for sell once you register.

So, make sure you register and start promoting their service!