Another hint pointing at Dark Sun in the future, or at least one that shows they are looking at it is that one of the earliest online dragons had a dark sun supplement which took old dark sun traps and updated them for 4th edition. I can't remember which dragon it was, but the traps were the "spider cactus" and some kind underground fly-trap thingy.
I hope Dark sun happens. I love Eberron, but now that so much time has passed since it's original release, I feel like the whole "stalemate" after the "last war" is a really stale and stagnant tone and it doesn't carry anything exciting anymore. Eberron could use a new catastrophe. Or a new war.