http://annys.eines.info/cgi-bin/man/...?localepurge+8
It's in debian, apt-get install localepurge, and it apparently deletes all the locales that you don't want to use. I configured it to leave "en" and it's variants, en_US and a couple of others, I think, then let it go and it freed a lot of space. I guess it installs itself and works when you install debs, deleting unwanted locale data that might be in the packages.
The do state: use at your own risk.