Is there any way to run some form of field control (starting and stopping matches, disabling robots, etc.) on the electronics?
Yes, there is a way to start and stop matches. We have released a schematic diagram showing how to stop and start matches (4 teams) with a single switch. Adjust the switch shown in the schematic for the number of transmitters you are controlling. Care must be taken to insure the cable is built correctly or you may damage your Transmitter. The schematic, Vex Competition Controller, is located on our Downloads page under Vex Documentation: http://www.vexlabs.com/vex-robotics-downloads.shtml