Maximus has posted a report of his trip over to Obsidian a week or so back to check out Mask of the Betrayer. He also links to one by the tileset gurus at Robinson's Workshop, though I haven't had a chance to read that one just yet.
Interestingly, Rogue Dao studios also had a chance to demo their upcoming module at this meeting. I've long been a fanboy of the Planescape setting, and from Maximus's description, and everything else I'd seen from it, it really sounds amazing. I'm actually much more excited about playing their module than the actual expansion campaign... In fact, I'd probably be willing to hold off on purchasing the explansion to see if I could snag the expansion as a Christmas gift, except that Rogue Dao's module will require the expansion!