Yes, from 1987-2010, there were 4 other games that featured a team that was favored by 20+ points. Each time, the team that was favored won, but failed to cover the spread:
1987 (Week 4): San Francisco 49ers @ Atlanta Falcons - The 49ers were a 23-point favorite. Although they failed to cover the spread, the 49ers won 25-17.
1993 (Week 14): Cincinnati Bengals @ San Francisco 49ers - The 49ers were a 23-point favorite. Again, the 49ers failed to cover the spread, but won 21-8.
2007 (Week 12): Philadelphia Eagles @ New England Patriots - The Patriots were a 24-point favorite. Atlhough, they failed to cover the spread, the Patriots held on to beat the Eagles 31-28.
2007 (Week 15): New York Jets @ New England Patriots - The Patriots were a 24.5-point favorite, making them the first team in NFL history to be 20+ point favorites multiple times in the same season. Again, the Patriots failed to cover the spread, but won 20-10.
@ Professional Liar - The 49ers were only 18-point favorites against the San Diego Chargers in Super Bowl XXIX.