"Lack of multiplayer is a temporary issue with Unreal2." This statement, posted on the Ataricommunity.com forums belongs to Epic's Vice President Mark Rein.
The multiplayer part of Unreal 2 had to be dropped, even though it had gone through a considerable part of the development process, in order to avoid delays and glitches during the UII launch. As a result multiplayer focus fell on Unreal Tournament 2003 which, after all is a multiplayer only game.
Mr. Rein also added Legend are currently reviving their XMP design for mulitplayer and it will be released as a FREE downloadable add-on for people who own Unreal2.
Since then Atari have gone on to confirm the project and to announce their support and backing towards Epic. No details of the time of release have been announced yet.