I had upgraded my Gentoo system beyond what was supported by the Xen kernel currently being offered by VPSLink. I did not want to re-image my container, so to downgrade everything back to acceptable versions, I created a Portage overlay in /usr/local/portage. For those of you who may also find yourselves in this situation, I am posting the overlay I created here on a GitHub account.
Note that this does not represent a complete solution to the problem. You will most likely encounter issues emerging some of these ebuilds, configuring your system, manually download distfiles, and be required to emerge other versions of packages. However, leveraging this overlay may help you to get underway, so I share it in the hopes that others using Gentoo on VPSLink may find it useful.
You can find a quick walkthrough on configuring a Portage overlay from GitHub at funtoo.org/Git_local_overlay.
Also, here are some relevant portions from a few Portage config files on my system.
#VPSLink needs to update kernel before any of the below can be emerged
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