As Google will often do, it is currently testing a new interface for its main search product. The experiment includes a top navigation style, eliminating the left panel completely. Every search option resides above the search results.
As Chitu notes, the interface shares some similarities with Google's current tablet experience, in that navigation is delivered horizontally above search results, though there are still some differences. For example, when you click "More" on a tablet, the options expand horizontally. In the video above, options expand into a vertical drop down menu.
There's a very good possibility we'll never see this interface come to fruition. Google runs over 20,000 search experiments a year. Still, the similarities to the tablet version may increase the odds that we'll see something similar. Google may be looking to create a more uniform experience across devices.