Honestly, the majority of electric tone comes from the electronics.
Also consider 'hybrid' designs such as Parker's fly - hardly a heavy guitar by any stretch of the imagination.
This vid of a CF cello being made is also quite interesting (if you ignore the terrible, terrible music):
http://www.youtube.com/watch?v=J_gI3chGtwwAlso check out Blackbird guitars (monocoque CF acoustics), CA guitars and Rainsong for acoustics, and there are quite a few small builders doing all-CF electrics. All tend to tout the 'superior acoustic properties' of composites - sound clips certainly lead me to believe that a pretty dang nice can be made from CF, but I like working with wood too much to give it up
EDIT: might want to read the relevant forum sections here as well:
http://macnichol.com/forum