Xspice is an X server and Spice server in one. It consists of a wrapper script for executing Xorg with the right parameters and environment variables, a module names spiceqxl_drv.so implementing three drivers: a video mostly identical code to the guest qxl X driver, and keyboard and mouse reading from the spice inputs channel.
Xspice allows regular X connections, while a spice client provides the keyboard and mouse and video output.