Well...it doesn't look like we're getting on-screen palm blocking, but there's hope.
The new Touch Cover tech (or 'Blades') has over 1000 touch pressure points, and Microsoft is looking to offer a series of Blades with different functions (e.g. Remix Project).
We might see a Blade/Cover with legitimate pen and inking capability. What Tegra Note offers is just palm block, what a "Write Cover" could offer is multiple pressure points on top of palm blocking, i.e. an active-digitizer like experience.
Now here's the thing. It wouldn't be enough to just have this blank cover. Sure, such a thing might be useful for creative professionals, effectively giving them a "Wacom on the go" like experience, but not for say a general professional. What a pro needs is a Touch Cover keyboard that doubles as a writing pad.
Imagine this. I am typing notes, and then suddenly I need to draw a diagram. Let's say I have this special stylus and I then bring it close to my Touch Cover...the backlight then forms around the outer rectangle, indicating that the 'keyboard' is now a pad, and I proceed. Granted this will need to be a new Cover, the keys need to be embedded in deeper and the layout altered slightly, but you get the gist. This could be a neat proposition.