I know, there's little point as you can get a better picture on something else for less effort and small $, but I think it would be interesting.
From what I can see, it may not be that hard. Obviously half of the circuitry would be redundant, the part involved in recieving and decoding the analogue signal, but I'm wondering if the part that takes this data and feeds it to the GT would be able to handle a similar digital signal from another source?