Actually i believe it IS possible, the more i read about glx the more possible it seems, but it won't have a tiny footprint, there would have to be another instance of much of the Xserver, and it gets trick because the needs to be some clean shared memory between the two so that nvidia's glx module can call all the symbols from their driver and vice versa. But it REALLY is possible, then it would also be possible to implement glx remote rendering for all three glx implementations at the same time... Doing this would take a fair amount of work... But is entirely possible, but as I was saying before, it WOULD take a fair amount of work...
But it may be easier and cleaner just to have multiple xservers running simultaneously
, that way there could be multiple module paths, even multiple config files, and it would really eliminate the need to this hack.