I do remember a few years back that Dead Angel seceded from, I think, Luz de Bia, in Beluaterra to form Caras Galadhon whilst also ruling Avalon. I'm fairly sure he was ruler of both realms for a fair while simultaneously. I'm inclined to think you probably could lead a rebellion and if successful, gain a council position elsewhere. Though it could be you lead the rebellion and simply get passed over. Only one way to find out for certain ;-)