As seen here, I came up with a rule mod for those characters seen in anime with psionic/magic powers that pilot giant robots. After further thought on the subject I've come up with another modification.
To model a mecha that contains systems to enhance the pilot's power the mecha must dedicate one system to that purpose. This is similar to the Exotic Terrain/Environmental Systems optional rule on page 96 of the rulebook. If this system is discarded to damage then the pilot can no longer roll Purple dice.