To say that I am embarrassed would be a total understatement.
As I said in my original post I have been away from YR for a few years now and I some how had it in my mind that editing the RA2MD.ini file didn't work like it did with RA2.ini.
I think it could be that in RA2 the main menu is changed to the desired resolution, whereas in YR it doesn't change. I think that's what made me think I remembered it wasn't possible.
So, umm yeah, please disregard this thread. feel free to delete it.