Q: I am looking for a iPhone 3G Bluetooth Headset Dual Dock as I can’t find a second generation anywere. Can you help?
A: Unfortunately, Apple never actually made a Bluetooth Headset Dual Dock for the iPhone 3G. Only the standalone iPhone 3G Dock was ever released by Apple. Further, since Apple never released the specifications for their Bluetooth headset charging interface, no third-party product manufacturers ever produced an Bluetooth Headset Dual Dock either.
Since Apple recently discontinued their Bluetooth Headset entirely, it seems unlikely that the iPhone 3G or even the next-generation iPhone will have a Dock available that also charges the Bluetooth headset. If you can track down an original iPhone Bluetooth Dual Dock you can attempt to physically modify it to fit the iPhone as the electrical connections are the same, however that’s likely going to be your only option other than using the Apple iPhone Bluetooth Travel cable.