More details on:
http://breaking-the-system.blogspot.com/2014/08/emulating-usb-devices-in-python-with-no.html
This code uses the USB/IP project: http://usbip.sourceforge.net/ to emulate usb devices.
In this example I showed how to emulate HID mouse device.
This code can be easily changed to support any usb device.
This code is very experimental, use with care.
In the HID example there is a bug with USB/IP driver that causes blue screen on de-attach:
http://sourceforge.net/p/usbip/discussion/418507/thread/7ff86875/?page=0
It doesnt happen with other devices I tested.