Sloan Wainwright, aunt of Rufus and sister of Loudon, just released a new Christmas album and she covers Queen's Thank God It's Christmas on the album.
It's pretty good. You can listen to a clip of it here: link
Forgot to mention that to find the christmas album, just scroll down a little. It is the third Sloan Wainright album on the discography list. It is called On A Night Before Christmas (Live).