Okay! I've discovered what's up with the no-keyboard-input problem.

The problem:
Basically Maemo's Matchbox WM is extra-strict with certain keyboard input related window parameters - it requires a bit to be set or it won't give the window keyboard focus. On the other hand libsdl (a dependency) apparently contains a bug which clears this bit if a window icon is set. See http://talk.maemo.org/showpost.php?p...4&postcount=20

This was why only some games refused keyboard input - these were the games that specified a window icon and thus triggered the libsdl bug.

The hackaround:
I added a couple of lines in /opt/renpy/renpy/game.py to basically unset any config values requesting window icons. To the best of my knowledge Maemo 5 doesn't display window icons anyway so this is a nice and harmless workaround as far as I can tell, but it fixes the problem beautifully - now all my games obediently accept keyboard input, and combined with the keyboard-binding-switch hackround in my previous post, all my games are now fully playable

I have attached the modified game.py file in case anyone might want it.