The Google Price Index

Tyler Cowen points to this article on Google Chief Economist Hal Varian's attempt at constructing a new price index based on web prices:

On typing ‘pepper grinder’ into Google Shopping, Mr Varian was struck by the list of prices. “What’s the first thing you want to do if you’re an economist? You want to construct a price index,” Mr Varian said.

I'd like to see this happen. The Google Price Index (GPI) would be an interesting indicator of real-time prices. Especially with Google's prowess in presenting data, such an index would -- at the very least -- be fun.