If you are planning on doing this for buisness, then the ethical thing to do would be to design your own. If you get together with a manufacturer, which you will have to do to mass produce the component boards, they may be able to help you. Even if you don't care about copying a design, you will work harder to replicate their chip than you would have to to make your own design.
On a side note, I have been working on learning how to make RCs and as I make the project and learn I am developing a tutorial walk through of it at the same time, when its done and refined I will make it availible in the projects section here and you are free to use it.