The History of the Blues: Frances Davis (well researched and a decent read too. You'll learn alot about the ties between jazz and blues ala W.C. Handy to Robert Johnson and beyond. It's not sepcifically about the guitar but you'll pick up some interesting tidbits. For example how the guitar stepped from pure acoustic to resonators/dobros to electric...etc)
and
Rock and Roll - an unruly history: Robert Palmer. This is the companion book to a series that was on PBS a while back. Nicely done. Easy read and very detailed.
and finally:
Deep Blue: Robert Palmer. Also a very well written book. Good stuff.
I too am a little envious of your project. I think I would have fun writing something like that back in school. Should make for interesting reading which means it should be an interesting paper to write. Again, good luck.
[FONT=Tahoma]"All I can do is be me ... whoever that is". Bob Dylan [/FONT]