Does anyone know if there are any applications other than the default ones that can be integrated into the homescreen feed. I really hate the twitter and facebook default applications. They are laggy and slow.

Is it even possible for 3rd party applications to be integrated into the system right now?
like wazzap availability/chat options in messaging and contacts.
FMobi as the default facebook application?
Tweetian as the default twitter application?
or is that stuff only possible when we have the source code of Meego Harmattan?
I'm not being ungrateful or anything but if status menu extensions can be done, then could this be done too?