Have there been reports of botnets mining Bitcoin / crypto-currencies? Is the threat of Botnets using massive amounts of CPUs/GPUs to mine Bitcoin, or some CPU-friendly coin, purely theoretical at this point? Or have there been reports of this actually happening?

I know of trojans stealing Bitcoin wallets, this is not related to my question.
First report about mining botnet was made at the end of June, and it evolved rapidly from CPU to GPU mining. But there is no consensus about what kind of harm it will do to Bitcoin, because from the bitcoin network point of view, infected computers run legitimate mining that supports network operation.


17 Jun 2011 - Symantec suggested that it would be profitable to
run CPU mining botnet.
28 Jun 2011 - Kaspersky Lab's expert Alex Gostev made first
report about simple CPU mining botnet found in the wild.
2 Aug 2011  - F-Secure reported about discovery of advanced CPU
mining botnet controlled via twitter.
11 Aug 2011 - Symantec discovered first GPU mining botnet called
Trojan.Badminer.