For anyone who's curious enough to try it out:
http://store.neurosky.com/products/mindwave-1
There are some Youtube videos of EEG devices controlling robots. Unfortunately, consumer grade EEG devices are still in their infancy. Also, IIRC, you need to be completely relaxed when using it, which makes me think it's a bad idea for FRC since I don't know any driver or manipulator player that's completely relaxed during competition.