Earlier it was very difficult to find a theme for BlogEngine, since there were very small number of themes available. otherwise you you should be one who know these html and other things then you can create one. Now the things changed, the BlogEngine community is getting stronger and there are many themes available in the net now. (Even i have created few)

OneSoft -  here you can find many BlogEngine themes.k so just have look on that site, if you are a BlogEngine blogging platform user, you may find another good theme for your blog.

Themes4BlogEngine is one place where you can see a collection of BlogEngine themes created by many. He is just sharing it but still that is a great effort.