Just from looking at the links you posted, I think you picked some good motors and a good motor controller. Just be careful that you keep the voltage under 16V and the average current around 13A so that you don't break your controller. Considering that the motor takes 3.6A without any load, and it stalls at 130A, you'll probably need to be most wary of the current draw. If you figure that you're using 3.6A at 0 oz-in, and 130A at 2500 oz-in (both at only 14V), you can do a rough interpolation to figure out what current you'll be drawing for the average torque that you'll need.
I'm not sure why you need it to go a full 5mph. In general, people are understanding of robots, so they will go a bit slower than normal to follow one. It is also important to consider safety. Your robot will need to sense and react to objects in its environment, and accurate, reliable sensors usually don't have great range. You don't want a 60lb mass of metal flying along at 5mph to hit some little old lady standing in the hallway. Also, if you reconsider your need for speed, you won't strain your motor controller or cut into your battery life as much.
Good job finding such inexpensive, powerful motors! I have found that motors tend to be the most expensive part of my projects. You really have to dig to find good deals since everyone posts different stats and prices.
Good luck! Keep us updated!