Some Stiller news (with excerpts):

DeVito to Direct Stiller Comedy
"Duplex'' revolves around a New York couple who dream of moving into a coveted duplex apartment, but must first murder the kind old woman who lives in it. The script was written by Larry Doyle, a supervising producer on ``The Simpsons (news - Y! TV).''
Ben Stiller talks Meet the Parents 2
So what's the delay? Well, Universal says the ''Fockers'' script is still in the works. And says Stiller, who's getting ready to start shooting ''Duplex'' opposite Drew Barrymore, ''I don't know what's going on with it. Comedy sequels are tough... because so much is based on the freshness of it. So, if they can figure out a way to do it, it would be great. But no one wants to make something that's just going out there to do it again.'' In other words, it looks like we'll have to wait a little longer to meet ''Mother Focker.''
That first one sounds especially funny. Set to star Stiller and Drew Barrymore...if done well, it could be very, very funny.