Well,i admit that i didn't think about the Arduino pilot, that seems to be something very good.
Your links helped me, now i have to reput together all of my ideas.
Basically, i will be shooting nothing, but if a friend of mine accept, we will be doing some Air Combat.
The motors, i will need 3 motors for Hover mode and little movements in order to get some altitude, and then the 2 rear hover motors will switch to a horizontal state to help start the cruizer mode, where 2 other motors (maybe thermal motors) take the job of propulsion, but still not sure about that, it is not a definitive idea.