DMA and Demographic Info on Google Maps

It seems like it would be useful to create a DMA layer for Google Maps and mash it up with all sorts of other demographic and client-specific information. I poked around and found this:
- A really cool mash-up (pictured above) of Google Maps and US Census (2000) data.
- Analygis's tool that works a bit differently but uses the same information
- Retail marketplace data package from ESRI.

Please drop a comment if you know of anything else.