If you install shortcutd, you can configure it to emit the reflow key combination. This is the only solution I know for now...
You may want to the bookmarklet method again by modifying font.minimum-size.unicode (or something like that) instead. I haven't tried so I don't know if it'll work or not.
I tried the bookmarklet method for Diablo described in http://talk.maemo.org/showthread.php?t=18333 but it doesn't work in Fremantle Microb, at least in my hands.
Any idea? Maybe can be done with some dbus magics? Thanks
Ernesto de Bernardis