[Jmirko]

I believe the 300dpi e-ink display is not in any commercially available device yet. The one that comes closest is the Hanvon WISEreader E920, at 200dpi (1600x1200 pixels in a 9.7-inch screen).

Back to the topic of handwriting on e-ink: several members mentioned the Sony T1. I have tried it, and I think it's a great touch-screen reader, but not a good solution for handwriting, for 2 reasons.
First, the T1 hardware doesn't support hand rejection. This means you must be careful not to touch the screen with your hand while writing, otherwise you will end up with unwanted marks. This results in an unnatural hand posture which may be fine for quick scribbles, but definitely not for serious note-taking.
Second, the software does not support muiti-page scribbles - again an indication that heavy-duty note-taking was not the intention.

What you need for a good handwriting experience is a digitiser layer behind the screen (Wacom, N-Trig or similar), which allows accurate stylus calibration as well as hand rejection. I know three companies who make e-ink devices which can do this: Onyx, PocketBook, and Hanvon. (Careful though, not all of their models support handwriting!) Hanvon seems to be the most advanced of the three, offering e-readers which can switch automatically between finger touch and stylus input (hand rejection is turned on automatically when the stylus is near the screen). Onyx and PocketBook are stylus only. Incidentally, the color Jetbook shown in the video above is also sold by Hanvon as the C920 - so they really are pioneers in applying the latest eInk technologies. Unfortunately Hanvon products are scarce and poorly supported in Europe, they seem to be focusing on the Chinese and Russian markets.

I bought an Onyx Boox M92 a few days ago. The note-taking experience was a bit disappointing out of the box, but with the latest firmware, both stylus calibration and other functions (rename, search) are fine. The e-ink screen has great contrast, but the Asus EeeNote EA-800 still offers better value in my opinion, due to more reliable and ergonomic software, audio recording, camera, and lower price (about half of the M92).
I have not tried PocketBook or Hanvon products yet, so I cannot comment on those.