I have a huge list of ideas for a slicer. From easy to complex. But before starting from scratch, look at what is out there. Slic3r is there, but with it's perl based. And still has some design flaws IMHO (not as many as SF).
Cura is currently SF based, and I used to advertise that quite large, but as Enrique has no interest in 3D printing, the code is a huge mess, and I was not credited for updates in SF. I feel little need to credit SF more then I have to. Also, people read "SF" and instantly discarded it as crap.
As for a C++ slicer. First take a look at MircleGrue, it's the C++ OpenSource slicer by MakerBot. They are not using it for high quality prints, but I don't know why. (They still use SF50 for that, without any tweaks that I did to improve SF)
EDIT: Also, I've been quite clear about this. Cura IS and will remain OpenSource, and will remain supporting RepRaps. We will always have a free software option. However, putting the Cura interface on top of a !optional! payed slicing engine is surely an option, as this will give a consistent interface for bot the free and payed slicers. We also think that having a good free option will press the payed option to be even better.