besides it being the #1 movie ever before POTC came along and beat it..
all jokes aside there have been rumors about it from Entourage. Cameron has even said people have no told him he should really do it.
In a true display of life imitating art, rumors began to surface during the second season that James Cameron actually was in talks with Warner Bros to helm an Aquaman feature film starring Mark Wahlberg. Ultimately this proved to be false, with Aquaman appearing in The WB's Smallville several months later and eventually surfacing in his own (ultimately failed) pilot titled Mercy Reef.