Ok. This rumour has been going on way too long to be just a "rumour"
Hakkinen is seriously thinking of a return. This has been said by many people who know Mika, including his ex-manager Rosberg and Ron Dennis to mention a few.
But williams has already filled both it's places. Vey unlikely position. Anyway, the latest rumour has it that Hakkinen demands a salary of something like 20-30 million euro's. Definately not a Williams salary. Bar too seems unlikely. So lets think about it. What team still has a place open, has that kind of money, one of the most powerful engines on the grid, and a serious aim of world championship in a two year timeline? That's right... Toyota! I wonder why this hasn't been mentioned as one of Hakkinens possibilities. Their options are Trulli or Hakkinen... I would go for Hakkinen, as Trulli left Renault for money, and i would rather put my money on hakkinen than Trulli.
Hakkinen doesn't make mistakes, whereas Trulli is no stranger to them, and that mistake for Barrichello was just unforgivable.
Would be nice to see Hakkinen beat R. Schumacher's ass and show how much Ralf really is worth.