My guess is a guitar that turns into a saber. 2 birds and all.
A couple of years back, I did build a saber guitar out of some scraps I had laying around. It had Hasbro saber electronics wired in to the output and an led fretboard. It was also unplayable, mainly because the scraps I had laying around were scraps for a reason.
And I'm of a mind to say that the saber I've spent the last few days designing would probably be better as a standalone than a contest entry. I could get it to work within the criteria, but it'd be stretching the rules a bit. Which normally, I wouldn't mind, but seeing as I wrote the rules this time, I should probably stick to them. At least try and set a standard.