A first shot at a x64 package for 13.1: http://gaia.homelinux.org/salix/miscpac ... -428ab.txz
Notice, it's only a very first version and also I'm writing this from that chromium build, no guarantees. It's especially missing stuff like icons, menu entry, etc still. If I got some time and feel like it, I might make a SLKBUILD from that SlackBuild thenktor posted incorporating also the changes from his chromium package. And if I get a working 32bit chroot, there might also be a 32bit build.
Don't be careless about building this. Expect around 11GB of memory usage!!! Don't set JOBS higher than your number of cores. I suggest you build with nice -n19 and ccache. The first one hopefully minimizes freezes (your system is unresponsive for hours though) and ccache allows you to rebuild nearly as if it was a normal package (i.e. much less memory usage and a mostly responsive system).