nvidia-glx-1.0.6629-r1 (latest stable on amd64) and nvidia-glx-1.0.6111-r1 have the following line: PDEPEND="amd64? ( multilib? ( >=app-emulation/emul-linux-x86-nvidia-${PV} ) as with 2005.0 the multilib use flag is always disabled, the users no longer get a multilib-enabled version of the package. simply removing the multilib? won't work, as this will lead to wrong behaviour on 2004.3 machines, so how are we going to fix that?
those versions are phased out. They need the later ones on 2005.0... Those old ones should be in package.mask on 2005.0. Use the latest stable.
app-emulation/emul-linux-x86-nvidia <media-video/nvidia-glx-1.0.6629-r3 are both in 2005.0/package.mask, nvidia-glx-1.0.6629-r5 is stable