Géant !
I just updated Movable Type to 3.17 and noticed that I don’t need one of my hacks anymore. I had modified dirify in Util.pm to convert two-byte UTF-8 characters to their unaccented equivalent. It allowed nicer URLs to entries with accented characters in their title like, for this one, ‘geant.html’ instead of ‘gant.html’.
Movable Type 3.17 implements this very similarly to how I did it. Moreover, it examines the PublishCharset configuration variable to determine how dirify should behave (which I didn’t, it was a hack). The only catch is that it’s case sensitive. PublishCharset must be set to utf-8 (and not UTF-8) for it to work, so check your mt.cfg.