This doesn't work well when you have to add up to seven links per wiki for each page that's added. It gets even worse if people start moving the pages around.
Fortunately, we live in a world of automation. I finally got everything setup to run the interwiki script of the python wikipediabot.
Fun points of discovery before reaching that point included:
* Python doesn't like uppercase array keys - like "WikiFur"
* Our new anti-bot extensions were working as designed, and blocking all the edits the bot tried to make
* GoDaddy's forwarding breaks on non-US characters (which led to moving all the *.wikifur.com redirects onto the new wikifur.com server)
* Wikia's "credit" links (added to all exports) were going to be added to pages edited with the bot as well, until they were filtered out (thanks to a certain member of #wikia for pointing out the patch)
* Actually getting interwiki prefixes added on the English edition is a manual process if the target isn't a Wikia site (es: and ru: have not been added for cs, de, fr or pt; this will be fixed after the move of those wikis)
The result was worth it, though: Lotsa edits from ReaperBot!
(Thanks to the magic of the bot flag, you only see them if you have "show bots" turned on for the English, Russian and Spanish editions.)
Bear in mind that this bot only works if you do make an interlanguage link at least one way. It does not automatically connect articles with the same title, although it can be run in a mode that asks for hints for articles with no such links. So, if you're translating a page, make sure you at least link back to the original.