Interesting idea... I think you can definitely parallel the development of both the design and materials, and I would say that to give the full breadth, you have to look at the whole history. I think electric guitars represent the latest evolution in the design of the guitar, not a separate branch, and the two types have definitely influenced each other. While Gibson and National and other's early designs were somewhat evolutionary, Fender's early futurist designs were revolutionary, then came Ibanez and others whose designs are hard to categorize - the Iceman? Ovation's Deacon?
Looking backward, you can easily see the baroque influence in early guitar designs, but that changed with the change in art and architecture styles, and the design of guitars had definite "schools" throughout Europe and America, particularly Spain, but guitar design can be divided here too, gut-strung versus steel-strung, which came with the Industrial revolution. Mass production had a big effect too - see Martin and Gibson's early history for more on that...
Good luck, I think you're on to something. Hope you post it somewhere we can read it when you're done!
dmz