Mike Blumenthal spotted this last week, where Google was testing showing not just the local pack carousel, but an ad slot in that local pack carousel. We've seen lots of variations of the local pack carousel - a scrollable carousel of local results. But this one has an ad unit and that ad unit sticks to the top above the organic local pack results.
Here is Mike's screen shot:
I suspect Google will be launching the carousel interface for the local pack at some point, but we will see.
Forum discussion at Twitter.