Not sure about being able to control on both the iPod and the HU, at least I don't know of any HU that doesn't lock this out for the iPod.
On the iPhone there are a few options. The Pioneer Avic-F90BT works the way you want AFAIK. I know it doesn't lock out the iPhone and it charges it. Not positive if you can change songs on the iPhone and have the newly selected song play on the HU. I do know if I start Pandora or Simplify it plays through the HU.
If you have an older non USB HU you can get an adapter that will allow charging on the iPhone and newer iPods. It is about $30 and all it does is change charging from firewire pins and converts to proper voltage, etc for the USB pins to charge the new units
On the iPhone there are a few options. The Pioneer Avic-F90BT works the way you want AFAIK. I know it doesn't lock out the iPhone and it charges it. Not positive if you can change songs on the iPhone and have the newly selected song play on the HU. I do know if I start Pandora or Simplify it plays through the HU.
If you have an older non USB HU you can get an adapter that will allow charging on the iPhone and newer iPods. It is about $30 and all it does is change charging from firewire pins and converts to proper voltage, etc for the USB pins to charge the new units