So far I have found 5 (fairly recent), but to be honest I am going to stop looking. FT-search isnt all that helpful and even google is hard to use because people use many terms other than karma (thanks/gratuity/good will/nothing/etc). The more I look at it, this might be better served with a master thread within the forum, similar to the "premium class" thread in the MR forum. A "Karma Master Thread" of sorts.
I would like input from others on this because I wouldn't feel comfortable starting such a thread in case it was deemed to be either unnecessary or inappropriate.