As I've noted earlier in this thread, the Supreme Court could curtail the abuses caused by its earlier ruling, without having to contradict it, by finding that DUI checkpoints are constitutional if and only if they are restricted to either (1) looking for people who are DUI, and (2) acting upon prima-facie plain-view evidence that a crime has been committed. It should not be sufficient to have probable cause to believe a crime may have been committed; prima facie evidence of the actual crime would be required (e.g. if a cop pulls over a motorist and observes a bullet-ridden corpse in the passenger seat, the cop should be entitled to investigate it).
I wish the Supreme Court would take steps in the direction you describe. Of course, I believe the Supreme Court should reverse its position authorizing such checkpoints, as painful as it may be for them to reverse precedent.