I will admit that AP Katarina might be stronger. But trying other op stuff, i find very fun! I think u should try this out. For me it worked out pretty good! AD LONG LIVE, and u may have a great summer 2012!

I take these runes because i wanna keep this ad up, but still be armor and MR op

I think Flash / Ignite is very good in every lane. U have a chance to handle ganks, escaping, and finishing off targets.

In teamfights, take the carry down first. u can hunt him with Shunpo as your team kills the others, and from there u throwed ur Knife (Q) to make an assist, there, the shunpo will reset and u can hunt the carry easily that way.

Farming is very easy in this build. With ur Q u can take last-hits, and still harass ur opponent!