I may have hit upon something here, unless I'm completely missing something. I didn't completely read through the previous two threads, but I did skim them, so pardon me if it's been mentioned before.
Just a few minutes ago, I was a little bored, so I made a save and decided to go on a murdering spree in Skaal Village. When I killed Fanari Strong-Voice a quest update popped up stating, "Failed: Kill the leader of Hrodulf's House." I didn't remember ever seeing such a quest, so I jumped on the ol' Google Machine, which lead me to this series of threads, and a few other random threads on some other boards. After skimming them all, I didn't see any mention of this particular development.
So maybe a quest we haven't found the activation for . . . or an unfinished quest?
Wait! I just remembered. The chief of the Skaal gives out bandit missions. There are bandits in Hrodulf's House. Sorry, dead end again.
I didn't know the Chief gave out bandit missions? Learn something new every day

As for the find, kudos to you, but obviously been solved already

Ah, darn. Somehow I've never seen any of those quests. And I didn't see any active for killing the leader of Hrodulf's House when I looked in my Quest Log. Odd.
Well, crap. Sorry for the interruption then! Go about your normal business, nothing to see here, etc.
No, by all means thank you for showing an interest in this ever growing thread
