Coincidentally, yesterday I released a MediaWiki extension which, if accepted on Wikimedia projects, may make interwiki bots much less busy. See http://meta.wikimedia.org/wiki/A_newer_look_at_the_interwiki_link
Interesting. I have thought quite a bit about interwiki-links myself, and studied some spectes of them for my thesis. A short writeup of a slightly different proposal for interwiki-linking can be found here:
http://brightbyte.de/page/Ideas_for_a_smarter_inter-language_link_system
It works with a central database, but without a central wiki, and keeps interwiki-maintenance largely "in-place".
-- Daniel