After joining the Midas Magic fraternity I found that the questline was never actually completed, and now I'm stuck with a constant current quest tab and a faction on my membership page which I can't get rid of.
Do any mods exist that can help me fix this problem?

Quest log manager?
http://www.tesnexus.com/downloads/file.php?id=32266

That doesn't allow you to delete quests, but you can hide them, which I find very. very useful.