Highlander: The Game is now no longer in development. This was confirmed to IGN by a Square Enix representative today. Highlander was announced back in 2005 and was in the works for Xbox 360, PS3 and PC.
Highlander: The Game was to be based around the Highlander film series, which all started with the original Highlander film, released in 1986.
The game was originally being published by Eidos, who were unable to give any details or reasons for the game's cancellation. French company WideScreen Games were handling development.