The rumors are true.
Several media outlets recently reported that Midway's Haven: Call of the King, developed by Traveller's Tales, had been canceled for GameCube. Today Midway confirmed the reports to us, saying that both the GameCube and Xbox versions were originally planned but have since been nixed.
There is no official explanation of the cancellation, but the company likely decided that the ports wouldn't be profitable. The original PS2 version faced poor sales amidst the holiday onslaught of titles, despite some critical acclaim.