Thanks to a reader, we have located the 1920 census image for "Santa Clause" in southern Missouri. He's not living with Mrs. Clause, although his WW1 draft card indicates he is married at that time. He signed the card, "Santy Clause" which is kinda cute.
The images of the draft card and the 1920 census can be viewed at:
http://www.rootdig.com/santa/