Pathfinder!
Mmmmm! I to have an idea for running a 2 or 3 player game, I don't know about the mythic part.
What level were you thinking?
I'm running a pathfinder game now and would consider starting another.
My thought was A couple of characters entering a huge legendary city, port city both above and below ground. Where anything goes as long as you don't go against the house of mayors that govern the city. Every race is welcome in the "Freedom City" it is said you can find or do what ever your darkest desires in Freedom City.
It's a home made adventure, filled with danger, adventure and mystery.