Maybe some of the stereo studs/studettes can help out.

As our fleet of Suburbans build (some have stereos and some don't) I'd like to convert all of them to just have a plate where the stereo was that has a single jack to accept a portable MP3 player input and maybe some fade/balance control. It would seem they don't put out enough gusto to kick up the volume to the speakers but surely someone out there has an in-dash solution. Again I don't want/need a stereo I'm just looking for something simple and fairly inexpensive to put in my vehicles. That way no matter which vehicle I drive I can just do like the Glade commercials, "Plug it in, plug it in!"

Just velcro my mp3 player on the plate with the jack and I'd be good to go would be the idea.

Thank you for your time.