[EricH]

No. That would be entering two robots into the 2011 FRC, which is a violation of the following rule:

<R10> Each registered FRC team can enter ONE (1) ROBOT into the 2011 FRC. That ROBOT shall fully comply with all rules specified in the 2011 FRC Game Manual.

I can understand how you could make the case that it's not a violation, especially if the robots are identical, but the rule is the rule. What I would suggest doing instead is driving the wheels off the robot that stays home to practice, then taking parts off of it to use as spares for the robot that is competing. Between events, put those parts back on, practice more and harder, and repeat for the second event.