Yeah, I made this guide because I've seen nobody tried the hybrid Miss Fortune, and only some few (squishy) full AP guides are shown on this site. The pick of Nashor's Tooth at early game caused some really interesting discussions with my friends so I decided to explain it here for everyone to try. I have to say, either way, that it works really good for me.
The choice is based, mostly, because it gives us attack speed on the first place and cooldown reduction on the second, and on the other hand, because it empowers the slow ability of Miss Fortune, with a perfect range to farm and which is good either to run from better ad carries, or to kill faster on early game, which will give us a really nice advantage. Although, seeing our critical strikes grow as soon as we have some farm done is really encouraging.
That's the other part of the build, our goal is to improve our critical strikes by getting some attack speed (again the Nashor) and some other items to do more dammage. That sustains on a prepared selection of the masteries and runes, and will be really helpful on mid/late game and teemfights, giving us the choice to backdoor if we need, to push quickly some lanes, and (if we follow the item order) not to die the first on team fights.

We get flash because it's the most obvious choice, but the barrier will help us to stay alive in case we face a really op support (like Blitzcrank) or at the teamfights. Think of it more like the Zonya's Hourglass active, just not that op.

First picks

Just a normal first pick.

Early Game

This is where the rare items are. We pick Nashor's tooth because it will give us advantage versus slower adcs, and will empower some of our abilities (w, and most of all, e) to help us slow down the enemies wether is to kill them or to run from them. Then we start with the critical strikes.

Mid Game

This part of the game is focused on gettin critical strikes and more damage while we prepare for some of the items on late game.

Late Game

This one is based on a) Survival in teamfights (the angel is the first pick and getting a health item will help us to resurrect with more life) and b) get more dammage so we can kill as soon as we get back to life.

Basically scale faster the E so we can use our first picks properly, and then scale the Q the latest, when we're getting more dammage. W is right anytime and R must be upgraded as soon as we can.

We don't really need the ap masteries because we're not making a full ap champ, not even a bot ap carry. Our ap choices are really limited and based on a little advantage against adcs, supports, and basically farming better.

We use only 2 gliphs of AP to have some advantage on the scaling of W and E, and because we won't normally face strong AP champions until late game, when we get some magic ressistance with the items. Then we empower the critical strikes with some marks and a quint.

Tell me if you try this what were the results, and vote either you liked it or not. But fisrt, give it a try! I've already been judged for the choices, just say it's bad when you have tried and it really didn't work.

Bye!