Tried this out yesterday, works perfectly! Thanks a lot!
The next steps:
I see 2 options now:
- Building a Wifi client, probably based on an ESP8266 Wifi module.
[+] cableless
[-] would need to disable Wifi suspension on the Kobo. Haven't got any idea yet how this is done.
[-] probably a battery drain
- Building an USB client
[+] no WIFI needed, no battery drain
[-] cable
[-] still have to find out how to enable USB-network support on the new 3.19.5761 firmware release
I will not have that much time in the near future, so some time to contemplate..

Suggestions and ideas welcome!