The 1200 was used as an early variant of a kneeboard moving map. The guys that built this (NAWCAD) are a great group of individuals that I've had the pleasure to be in contact with on another project they are working on. Now that I know this, there are some questions I need to ask them... like what hardware hacks did they do to the 1200.
I just finished hooking up a Garmin GPS-35 HVS to one of my 1200s for a friend to use as a moving map. The GPS-35 comes in a low power version which can draw power from the PS/2 port. Took 15 mins to wire up a serial adapter and a PS/2 connector. Current draw is mucho low. The GPS-35 isn't cheap ($185) but it does allow for higher speeds (> 99 knots) making it perfect for use in the aviation field.