I have not found the mandated receiver/converters in my area either. I checked both Wal-Mart and Circuit City. Have not checked Best Buy or Frys as they are farther from my house.
However, I did see the item below on Newegg.com. It appears to have the RF output, am not sure. It is not the one that I have with the composite output.
http://www.newegg.com/Product/Produc...82E16882107064
One note about Newegg, if a product is defective, it must be returned to the manufacturer, Newegg will not take it back.