A dealer will not install the factory NAV system. The only way to get it from the dealer is delivered from the factory. But as supertester says, people have figured out how to obtain a factory NAV system (they show up from time to time on EBay from wrecked cars) and install it. They key is to get a factory NAV system that is hybrid capable, which is a different part# than the non-hybrid NAV system. The non-hybrid NAV system would work fine except you wouldn't get all the hybrid-specific energy screens.
If you are going to install an aftermarket non-factory system, then the bluetooth controls on the steering wheel will never work, or at least not until somebody makes a special adaptor for it.
The only other "factory lookalike" system that I've seen other than the OERADIO system is this one from Valor Multimedia. This unit is being sold by several dealers on EBay.
http://www.valormultimedia.com/