high voltage and high capacity will give you best run time. 6s is the most you can run on the mmm so go with that for voltage.
http://scriptasylum.com/rc_speed/_top_speed.html That is a great tool!
You should select a motor that will operate around 35,000RPMs+/- 5,000 on 22.2v and gear it for the top speed you want. Pretty much anything will handle walking-jogging speed as long as your throttle finger cooperates!. If this is going to be your first brushless build I suggest you start saving some money and do it right the first time! The MMM is a good start, select a quality motor, some good LiPos and a charger that is capable of charging them at a 1C rate.