I really like my theme, I enjoy single column and simple looks, check it out if you want: http://ohhhkenneth.tumblr.com/

I can send you the code if you like it. It has customization features too.

You can search the archive for http://theme-hunter.tumblr.com since they're always reblogging posts about new themes. Hopefully you find something you can use!

I just search google images whenever I make my layouts and incorporate some of their styles. I also like tumblr themes so sometimes, they end up looking like that (minimalistic, etc.), haha.