Two more to add that aren't really under the radar, but have incredible K/9 rates are Joba Chamberlain and Rich Harden. They have a very good chance to be undervalued in leagues that count K/9.
You could consider going with a couple of middle relief pitchers over a starter too. It'll take an extra roster space and probably get a few less wins but there's lots of them that get 9+ k/9 while there aren't that many SP who do.
Gil Meche had a career-high K/9 last year with 183 strikeouts in 210 and 1/3. Not sure if that's an outlier, but you don't have to spend a relatively high pick to find out.
Later than that, I really like Manny Parra, Jonathan Sanchez, and Wandy Rodriguez.