Good point, Cosworth - I admit I hadn't thought of that. But maybe they could dress it up as a merger of the two teams, rather than a complete take-over. It makes so much sense for Toyota to to do that - they could stop beating their heads against the wall and Williams could survive as a racing team in its own right.
In fact, thinking about it, the end of 2007 would be the ideal time to do something like that. Ralf would be gone and rumour has it that Kimi will be at Toyota next year. Could we read that as Toyota-Williams? And that would be a powerful pairing, Kimi and Nico, perhaps with Wurz as test driver again. Trulli? Well, maybe they could pension him off to Red Bull or Super Aguri or somewhere...