2012-05-01: Support was added for Waymarked Trails. (Other news...)
Links to Wikimedia projects for multiple language variants.
From Template talk:Portal
For now, Wikimedia projects links direct to the main variant projects (for instance, Portal:be has link only to be.wikipedia.org, and it doesn't have one for be-x-old.wikipedia.org). The difficulty of this situation lies in using 'be-tarask' for translations (which is good), and 'be-x-old' for domain name (which is bad). Any ideas?
I think be/be-tarask is the only situation in which a different way of writing the same language has actually led to different Wikipedias. Feel free to find a solution for the link, but it's such a small edge case that I will not look into trying to address the issue you raised.