Friedmud sent word of this news item on Virtual Zone Hardware saying that a demonstration of the 64-bit version of UT2003 on AMD‘s 64-bit Hammer CPU was running on Linux. To quote the brief news item:
AMD has demonstrated the power of their Athlon 64 using the GeForce FX graphics card by running the Unreal Tournament 2003 64-bit Edition on the 64-bit Linux OS.
As Friedmud points out, this means that a 64-bit port of UT2003 exists running on Linux, that GeForce FX drivers also exist for Linux, and that all of these parts are running well enough for a trade show demonstration. The news item doesn’t say which distribution was used in the demo, but I believe that at least two main players are known to be working on 64-bit distributions. While it isn’t clear whether this port will be made available to the public, it is at least some very promising news.