4 motors on one controller worked fine for us with the new motors at our first Qualifier.
Don't confuse FRC and FTC. There is nothing in the FTC rules preventing 4 motors on one controller.
Also, from the LEGO Education site:
http://www.legoeducation.us/eng/prod...or_tetrix/1648
The HiTechnic DC Motor Controller for TETRIX® connects to an NXT Intelligent Brick sensor port and will enable you to control powerful DC gear motors for use with TETRIX robots. The controller has two H-bridge outputs to control the speed and direction of two DC gear motors and is designed to connect to the TETRIX hole pattern.
A four-motor robot can also be built by paralleling two motors to one channel. A total of four DC Motor Controllers for TETRIX and/or Servo Controllers for TETRIX can be daisy-chained to provide additional motor and/or servo outputs on each port.
--Scott