I now have access to Opteron based hardware and I am running an x86_64 Linux on it. The guys at Blackdown have just recently released a 64-bit JDK, read more at
SUN have also announced that they will release 1.5 on this platform (and it seems this release will include the Blackdown work).
Anyways, I could test running Aurora on this platform, if there is a way to get IDEA to accept running on the JDK version release by Blackdown. Currently, this release is called 1.4.2-rc1 (which is based on 1.4.2_03 so it shouldn't be that much incompatability in that end).