I recommend that you all read the argument transcript in Hernandez v. Mesa (the audio will be available tomorrow afternoon).
It turned out there was little discussion on qualified immunity, other than a couple of questions from the Chief and Justice Kennedy about whether qualified immunity can account for facts about the plaintiff (i.e., if case law shows that doing X violates the Constitution, does it matter that none of the case law involves a particular plaintiff or class of plaintiff). But there is a lot of discussion of Bivens, some of which offers a nice review and illustration of of the open questions in the doctrine. In particular, pay attention to questions Justices Breyer and Kagan challenging the notion of Bivens "extensions" and arguing that we can read SCOTUS case law to mean "there is a Bivens action for the Fourth Amendment unless it is the military," suggesting a more-wholesale approach.
Updated: Here is the audio.
Also, note something else that came up in during oral argument. The question was asked whether a § 1983 action would lie if a cross-border shooting involved a local police officer. The consensus is that the answer was no, because of the statutory text, which prohibits subjecting or causing to be subjected "any citizen of the United States or other person within the jurisdiction thereof" to the deprivation. But then, in what may have been a throw-away line or a mistake, the plaintiff's lawyer suggested that a Bivens action could lie against the police officer. This is something of an open issue. On the one hand, the presence of a congressionally created cause of action is an alternative statutory scheme. On the other, people have argued that recently enacted limits on § 1983 can be overcome through a Bivens action to enforce the Fourteenth Amendment.