According to http://stackoverflow.com/questions/1664816/is-there-a-way-to-force-c-uri-for-in-catalyst-to-generate-a-uri-that-begins-wi this may solve some/all of our MBS-5122 issues, since we already set using_frontend_proxy in the presumably-relevant cases. Assuming we're using a recent Catalyst, this should at least make c.uri_for (i.e. CSS and JS, plus most other links) work correctly.