I found the answer. PAC-Audio model AAI-CHY
can be inserted behind the radio. You can buy it here
Here are some more detail emailed to me from PAC:
Yes the AAI – CHY will work for the Jeep Commander and it will work for any one of the 4 radios that would have been factory installed in that vehicle. The only set back is that the vehicle can NOT have factory SAT radio and VES. If so, you will have to disconnect one of the 2 at the actual source.
I've used PAC's interface in an H2 and it worked amazingly. You of course you need to figure out how to take apart your front dash to access the back of the radio, but once you get there the installation is quite easy.