| I haven't heard about any carbon fibre bridges, if you mean the carbon fibre / epoxy matrix stuff that bows are made of.
There was some discussion here about those Moses graphite bridges and boards some time ago that you can probably track down. Closest I ever got to one was, the luthier on Vancouver Island I used to go to had one of the old, non-traditional shaped versions kicking around his shop, although I recall he was pretty skeptical about it - I seem to remember it being actually heavier than a maple bridge, which would seem to negate the advantage of using composites ... don't take it from me though, I believe Bob G actually installed one and wrote about it.
I suppose an advantage of CFRP is that you could make it extremely light - but you could just cut a Quarrington-style low-mass wooden bridge if that's what yer after. FWIW every carbon instrument I've seen (and played, in the case of a Luis and Clark cello that's kicking around a store in Vancouver) has had a wooden bridge on it. | 
