Since Nintendo did not want my money for the NES/NES-mini i just went ahead and used a Pi inside a Clone, it turns out it was really easy to do the mod (see video).
I have also added buttons external USB. Why is external USB that so important to many of you?
Finally used the leftovers from the Clone I was using to put it inside one of the controllers.
Now I got a ZNES instead, Zuper Neat Enterntainment Sytem. I do not think I would have used a NES or SNES very much, but i love my ZNES, using it mostly for Arcades right now, its great!
So thanks to Nintendo for not wanting my money, this is so much better!
Hope someone finds this usefull, and hey I'm sorry for the Swenglish.
First video, how to fit the Raspberry Pi
Video nr 2, how to connect working on/off buttons.
Nr, tips on how to add external USB...
Extra: added the internals from the Clone to a controller.