The Neo1973 has a touchscreen. The touchscreen can be used to control a pointer on the screen. Using communication to a PC the touchscreen can control the pointer on the PC. The communication can be either USB or Bluetooth. Using this it should be possible to emulate a simple graphics tablet.
Option: Display screen on smartphone
Depending on the bandwidth it may be possible to replicate either part of or a scaled down version of the PC's screen directly on the smartphone. To do this the driver must be a bit more advanced. It might consist of 2 parts: The graphics tablet driver and a facility to transfer the screen. VNC or FreeNX might solve this.
Option: Pressure sensitivity
The Neo1973 has a screen that is capable of multitouch, only the driver is missing. If multitouch is available, then pressure sensitivity may be possible: The harder you press the finger, the bigger the area your finger covers. If the sensitivity is really good you may be able to use a brush directly on the screen. The physical brush will also provide the tilt functionality.