MP3 in 2004 ML500

Anyone have any suggestions on an elegant way to play MP3's in a 2004 ML500?  By elegant I mean something that integrates somewhat with the MCS.

I have beel looking at installing a hardwired FM modulator in our ML to use my iPod to play over the MCS.  That is the best level of integration you will get, unless you want to spend around $1000 to have a company fit AV inputs to your MCS.

I am planning to install my modulator underneath the glove box.  I am going to simply leave a stereo cable tucked up underneath the dash in the passenger footwell area, to pull out when I want to play MP3's in the car.