I read an interview with Ade Edmondson recently where they asked him if they'd ever do anymore.
He said that they'd always said no because Rik didn't want to.. but recently Rik had changed his mind and was mulling over an idea of them both being in an old folks home.
Found it on Wikipedia too
In September 2011, Edmondson appeared on the Sunday morning cooking show Something For The Weekend and confirmed to presenter Tim Lovejoy that he and Rik Mayall were planning to reunite and make another series of Bottom, set in an old people's home. However no specific dates were stated regarding the project.