This already happens. If you install any PyQt4 application you'll get those dependencies. Once those dependencies are install all PyQt4 applications will use them. This just means you aren't using any PyQt4 apps that require the dependencies mine does. But from here on forward.. all the apps that do share in a common dependency as mine will be significantly smaller downloads
It is possible the N800 shows it differently? Did you try rebooting the device? On mine it's in the "Extras" Menu, and has the same logo as is in the Application Manager. So I'm not sure where to troubleshoot there..
2) Nope.. using Mediabox's OSSOBackend solved this problem for me.. thanks .