Hi all,
before you waste lots of energy on discussion, be aware that the upcoming wikipedia software, which is currently in beta phase, supports variables in the text. For example, the date on the homepage is automatically adjusted when you view it, with things like "{{{CURRENTYEAR}}}" being replaced with 2001 (this year).
That system could be expanded with things like - {{{CATEGORY:Biology}}} in an article that could be seen as belonging to biology - {{{GERMAN:Haus}}} in the "house" article
These "variables" could be replaced for display with, say, a little German flag linked to the German version of the "house" article, named "Haus". These things don't have to be displayed inside the article, either; they can go to the header, for example, so you'd have some little flags next to the page title, or a category listing at the bottom.
That can be used for the category listing on recent changes (say, all non-categorized articles, and biology only). Furthermore, all international wikipedias could be checked once a day (or once a week), crosslinking languages. If the English article links to the German one, the German one will automatically link back to the English version. Also, if the German article links to the Swedish, but the English does not, both English and Swedish will be automatically updated.
This can be done without much trouble. We should wait for the software to be tested and implemented with the "current" features only, though. Once the new software is running wikipedia stable, all the other features can be added.
Magnus