What comes in my mind is complete ubuntu linux with gnome classic desktop on N900 successor.

I imagine that one day there will be comfiz fusion run on linux smartphone
because I think it will be a powerful thing to attract many people to use that smartphone.
The unique thing that you'll never find on any ios or android mobile phone. (cmiiw)


Why N900 successor?
because I think physical keyboard is always required for any smartphone but still with touchscreen support of course.

And don't forget a good hardware support to run comfiz fusion with good battery support.