why not use the android phone itself as a fake usb device?
i remember there're usb api for emulating that, and there're an fake usb cdrom app for people who want to use their andoid phone as a cdrom when they want to install os without cdrom :]
i think it would be cool to make an app which will fake as a usb keyboard and use the phone's camara to monitoring the target screen. then you could try to do some interesting thing