Thanks for all you comments! Here's the (wish/bug)list I have gathered so far:

- Fullscreen windows (conversations at least. Buddy list too ?)
- Working browser connection (Thanks for the dbus-send find!) I think I can implement the dbus-send stuff inside gaim and provide a new option called "OSSO Browser"
- I can try to reproduce the crash caused by receiving a message while typing on the fullscreen keyboard
- minimize to "system tray". I'm not sure what this means. I don't want to create a "system tray" icon, because the "system tray" (on the top right, between the window title and the minimize/close buttons) can easily become crowded. You might have noticed that you cannot quit gaim by closing the buddy list. I "stole" this idea from maemo-gaim, because I think that the panel icon can play the role of a system tray icon.
- The debug window needs a close button