Doubt it'll be more than 17 or so. The 07 Pats obliterated every line until Vegas quit putting lines up for their games for a couple of weeks, so that might happen to the Saints.
interesting question. fyi:
"According to Robert Walker, the Director of the Race and Sports Book at MGM Mirage in Vegas., the highest anyone can find is Steelers-Bucs in 1976. Pittsburgh was defending Super Bowl champ, the Bucs were first-year expansion babies who finished 0-14. The line was 24. The Steelers won, 42-0."
Largest Vegas Favorites in History as the Saints (8-0) will face-off against the (0-8) St. Louis Rams. Care to wager on the line for that one?
My guess is something like St. Louis (+27.5)