...what would it be about?
Basic ground rules:
1) We're going to assume canon = movies only. So no Mara Jade or Thrawn, or Kyle Katarn, or anything from the EU. You can create your own characters, but they cannot be based explicitly on any existing property from the various novels, comics, games, etc. Some leeway could be allowed for the non-movie spinoffs, such as the Clone Wars cartoons, though if you acknowledge them you'll have to accept the canonicity of the Holiday Special or the Ewok telefilms.
2) Do, however, feel free to use abandoned concepts from earlier drafts of the screenplays if they can be worked into the story.
3) You cannot retcon the prequels out of existence. You can ignore them as you see fit, but this is a universe that contains Naboo, Jar Jar (or his mortal remains), sassy battledroids, et al. If you deal with the history of the Skywalker clan you'll have to refer to the history as depicted in Eps. I-III.
4) The only dead character you can revive is Boba Fett. No Palpatine/Sidious, Anakin/Vader, or Zombie Padme. If we saw them die on screen, they remain that way, unless they come back as voices or friendly ghosts (original trilogy rules apply). No clones.