I know you said you tried `nth-of-type`, but have you tried `nth-child`?

Say for example you've added a class called `myrows` to your Views output (you can do this through the UI under style settings for anyone who doesn't know), then targetting every third row should be as simple as the following:

    .myrows {
      //Make all rows red
      color: #FF0000;
    }
    
    .myrows:nth-child(3n) {
      //Make every third row green (not including the first)
      //So 3, 6, 9, 12 etc will be green
      color: #00FF00
    }

[Here's a jsFiddle][1] just to show it working :)

*Some useful resources:*

 - [Useful :nth-child recipes][2]
 - [The Difference Between :nth-child and :nth-of-type][3]


  [1]: http://jsfiddle.net/rd2at/
  [2]: http://css-tricks.com/useful-nth-child-recipies/
  [3]: http://css-tricks.com/the-difference-between-nth-child-and-nth-of-type/