I've never heard this discussed in this English forum. There's more action in the German forum, but I don't remember seeing any discussion of installing Android onto the devices there, either. The most action is in the Russian forum at
http://www.the-ebook.org/. I don't know if the topic has ever been discussed there.
Bear in mind that E-Ink readers are not general purpose tablets or smart phones. The display hardware requires special handling. You'd probably have to look at what Onyx and Sony have done to get Android running on their devices, keeping in mind that each display needs its own special drivers (i.e. don't expect to copy an Android OS from another device and have it just work).
My uninformed guess is that you shouldn't expect to see Android on any existing PocketBook devices. I've heard that the upcoming large screen device will have Android, so maybe they'll produce a smaller ereader with Android after that. Who knows?
Finally, no recent PocketBook devices have been rooted as far as I know. If you wanted to install a different OS on one of their devices, you'd probably have to do some hardware hacking to do it.