I've believe I've read mid-January, though I can't find that source again. I'm quite excited for it, though I probably won't be buying one due to finances and already having a fantastic laptop. I'd love to have a pressure sensitive, capacitive tablet that has some power and a lot of portability. It sounds like it will have a lot of what I have now in my laptop, but smaller.
Heck, I might even be willing to sell my current laptop, then buy one (if it's reviewed well) and build a desktop.
Lenovo W520 w/ i7-2820QM, 16GiB 1333MHz DDR3 RAM, 120GB Corsair Force III SSD, Quadro 1000M, 1920x1080 LCD, HP w2207 (1680x1050), Windows 8
Motorola Droid 3