I saw this on Keith Baker's website today and I literally laughed out loud. As per Keith, it is a picture of Sharn, but that looks like a familiar face looking over the action on the city streets... 
http://www.bossythecow.com/Streets%20of%20Sharn.jpg
Catch the blurb about it on his site here...
My theory is that Eberron used to be connected to the planes, but they broke the connection way beack when (possibly when the Gatekeepers kicked all the Abberations out), so this could just be a holdover from back in the day. But the Lady is too cool for that, so she probably still has a few portals open somewhere.
Lol - possibly, but bear in mind that this pic is (as far as I can tell) in no way "official" or "cannon"... 
Hah! I've noticed that a lot of TSR and WotC alumni have a great fondness for Planescape. I guess good writers recognized quality when they saw it.
I know that a lot of people on the videogame sites I frequent still praise Planescape: Torment to the high heavens even when they know nothing about roleplaying.
It's hard to keep a good campaign setting down.
True dat (just look at the Misfits... 
)
Well, well, well. If that's not interesting. So Eberron is part of Planescape after all