After watching team 448X Ri3D, I thought of duplicating their design (quite literally). What if you had the same system of collecting and dispensing the cubes on each side of the robot? Meaning, on each side of the drive train (left and right) you would have a mechanism to collect and dispense large stacks of cubes. You would have to make each system more compact, but the weight would be balanced on each side of the robot. One problem to be solved is how to reduce the amount of motors for each stacking system. A reason to do this is so you can collect two rows of cubes at a time.
Link to 448X Ri3D: https://www.youtube.com/watch?v=QJI29QI5COM