I think I could find someplace to mount a second DIN unit rather than mount an AM/FM Radio hacked to accept the car's antenna or deal with it rolling around loose in my car. Have you thought about under dash or glove box?

I guess if you really wanted to go cheap, you could hook up an AM/FM walkman to your AUX port with a headphone/RCA converter. Get real fancy and you could get a DC converter so you do don't go through batteries.

You miss everything that empeg does with the module though. Hence, why it commands $400+ on eBay.