Yes ... not only are the Bills the only team to lose four consecutive Super Bowls they are the only team to ever play in four consecutive Super Bowls.
Marv Levy of the Buffalo Bills (Super Bowls XXV,XXVI, XXVII, and XXVIII).
Marv Levy of the Buffalo Bills
Minnesota Vikings in Super Bowls VIII and IX: Super Bowl VIII: Miami Dolphins 24, Vikings 7 Super Bowl IX: Pittsburgh Steelers 16, Vikings 6
The Minnesota VikingsThe Vikes lost Super Bowls IV, VIII, and IX. They also lost Super Bowl XI to become the first team to lose 4 Super Bowls.
Through Super Bowl XLII, the Dolphins record in Super Bowls is 2-3. Lost: Super Bowls VI, XVII, XIX Won: Super Bowls VII, VIII2
One Super Bowl
The Washington Redskins lost 2 Super Bowls XII and XVIII.
The Raiders and the Patriots.
The Minnesota Vikings (lost Super Bowls IV, VIII, and IX).