It's neither new, nor really overused, but I was thinking about it, and I wouldn't mind seeing the Kaiburr Crystal. I know it gets some EU attention, but as most of us aren't huge fans of the EU, and even there it hasn't gotten a lot of attention, I'll bet a lot of Star Wars fans, both purists and newbies alike would be relatively unexposed. It's an idea that deserves expansion, and it brings the Force more to the mystical side rather than the biological/midichlorian side. It's a classic MacGuffin that could drive home a fairly simplistic adventure tale, simply set in a galaxy far, far away. What made the OT so wonderful was not their complexity, but rather their unique retelling of very old motifs.