Those saying Tevez at West Ham should remember Macherano was there as well, and was just as important in a different way. For Shearer at Blackburn you had Sutton, Flowers, Hendry, Sherwood and later, Batty who were key members of that side. Bale for Wales is strong, but he still has Ramsey and Williams playing well alongside him.
It's very, very rare. Zlatan for Sweden or Ronaldo for Portugal (since Carvalho retired) are probably the closest thing to it. Even Baggio in 94, although he was the star performer, was part of a squad that included Pagliuca, Baresi, Maldini, Costacurta, Conte and Donadoni.