> Antitrust is another possible route: the only purpose of these patents is > to block interoperability.
This is a good point. But it'd be up to the AG to take the case. In the past there would have been little chance of that happening (recall that one of the earliest actions of Ashcroft after Bush was sworn in was to terminate the US vs. Microsoft suit). But Now that there's a new sheriff in town, this could turn up being an incredibly stupid move for Microsoft by demonstrating that they are still unrepentant monopolists.