The P-38 Lightning comes to mind when you ask about two fuselages. A very beautiful plane in my opinion: http://www.richard-seaman.com/Aircraft/AirShows/Chino2004/Sampler/P38.jpg
If you look at some of the planes Burt Rutan and Scaled Composites have done, you can find other examples, like Steve Fossets "Global Flyer" and others.

Have the A's even tried this? If they have, I guess their hullshape and length is is such that they dont need it to keep their rigs stable. Much the same reason the C-class dont use them.