I Suggest "Can o' Termites"
Well, a new world record was set at SanderFest 2009:
On Saturday, Sept. 12th, DJ Green Arrow set a new World Record for Longest Rap. At the "We Demand Transparency" conference, Green Arrow rapped for a total of just under 10 hours, according to guidelines set by Guinness World Records.
When asked why he attempted the record, Green responded that he "wants to put 9/11 Truth in the Guinness".
He rapped about 9/11 Truth for a good part of the attempt, even rapping directly to Richard Gage, putting Gage's story of how he founded AE911Truth.org into rhyme, causing Gage to dance.
I certainly hope we're going to get a YouTube of that. And:
He is still looking for the best rhymes for 'nanothermite' and will attempt to break his own record next year on 10/10/10.