Don't think much weight can be saved by introducing alternative materials on otherwise traditionally built steels. Too many design elements for the "strings on body" concept are fixed in form/shape/materials already.
Of course, for my own "strings on neck" concept nothing but the neck itself is somewhat "fixed" - for tone mainly, so I will probably be able to keep weight a bit lower than for a traditional build with same capacity without compromising on tone or mechanical stability. That's another cup of tea entirely though