A quick update:
The project seems to be dead.
Users on a german forum noticed, that the link to the german
press release does not work anymore (the
english version is still up, though).
After contacting Pocketbook to ask for the status of this project, the company replied:
"
Unfortunately, we have to inform you that we are currently unable to obtain displays [*note: meaning "Gallery 3" color displays]
from the E-Ink company as the technology is not yet mature. For this reason, the project is currently frozen and it is likely that it will no longer come to fruition."
[
Source - translated from german using Google translate]