Early days but carbon nanotubes look like a much more efficient way to gain performance in electric motors over copper windings.
Might be something for the experimenters to look into.
http://revolution-green.com/carbon-nanotube-windings-electric-motors/
Kind Regards
Mark
CNT-windings also good for power2weight-ratio-improvements:
http://worldwide.espacenet.com/publicationDetails/biblio?DB=EPODOC&II=0&ND=3&adjacent=true&locale=en_EP&FT=D&date=20010710&CC=US&NR=6259347B1&KC=B1