What holds for competition in this field, then we try the test.
Try to assemble a standard three-wheeled robot.
How to make this robot is written in the description of NXT. Although slightly different from the shape of the robot in "retail" and "educational" in using of the parts, there is no problem.

The third use of the motor, make a hand (additional parts of the original).
Two arm gear (Angle beam) will be opened and closed.

Sample robot has been completed. I think since it is using less part you can make only a basic set of NXT or NXT retail version.

Opens a hand to reverse the motor A, the hand is closed when the motor A rotate forward.