This thing shouldnt be any harder than the 2700g to add, on the 2700g there is only one pin and the avalibility of chips (intel and other big companies dont ship samples )
if you can get me a data sheet i can tell you if its posible and tell you what you need but without a driver its not worth the work, with the intel chip there are some details that could be used to make a driver but so far the x50v people havent got one
for the ATI chipset, yes i can get you code, look up betaplayer, he has code for ATI and intel chips and the code is open, at one point he was looking at getting the code to run under linux and i am sure if someone looked at it they could port it or port the decoding routines to mplayer (he compiles with the gnu toolsets for a start), the code fully takes into acount the sram caches and has been hand tuned, this and the new overlays would be quite nice