Peter, what is it that you do for the i18n? Are you only replacing the name fields with the appropriate name:xx?
I think it's even easier: we got views for each language that selects the right name:xx-tag and puts it into a virtual name field, so the only thing that needs to be changed is the table-prefix (from planet_osm_ to view_de_planet_osm_ or so). This can be done in the settings.xml, so we'll need a bunch of settings.xmls and a bunch of osm.xmls, right?
Peter