They were sneaky and hid it deep within the electronic corridors of the wiki but I still found it. But it's confirmed by Gaile on the talk page. It's coming out on the 29th. Not exactly a big surprise as you had to figure that “this month” meant “as late as we possibly can without looking like we're going back on our promise” in dev speak. I think I can safely speak for the entire GW NaNo club when I say, whew!
I was worried it was going to come out this Friday and take my weekend with it. By coming out at the end of the month it's not going to interfere with my closing death march across the keyboard of destiny. And, instead, it'll be a nice little treat waiting for me once I get this novel gone. You know, like GW:EN was supposed to be before I predictably broke down.
Granted, I shouldn't get my hopes up too much. The Costume Brawl which featured a similar “become someone else” mechanic was great but, when you get right down to it, the bars there were, by and large horrible. It's only because everything else was similarly suboptimal that it didn't matter and the even playing field could shine. The prospect of well-designed mission encounters that are difficult without simply having the quote unquote difficulty knob cranked up is probably a slim one. Instead, we're likely to get janky bars and missions designed for the general public - ie, so simple a microencephalic could do them. Frankly, I' expecting things like a meta-thievery bar for little Charr stomper Gwen - all echoes and arcane thieveries. I don't know what other characters you'll be running but I suspect it's going to be Hamstorm Warriors and touch Rangers and the like.
Still, bonus content is bonus content. And maybe, just maybe they'll be a shiny reward waiting for me for completing the thing. It'll probably have to wait until that weekend for me to get around to it, though.