Following up to my post two days ago, the news has now made it to golem.de.
AOpen wasn't quite happy about the bad press, so I was immediately contacted again. They're now working closely with their Taiwanese mother company to become GPL compliant ASAP. I'm eager to see the results, and hope that this issue can be put behind us soon.
However, I now re-discovered that the firmware image is actually download-able from ftp.aopen.de, a domain registered to the German subsidiary. So while the product might not have been sold in Germany, the firmware was actively distributed by Aopen Germany GmbH.