I've only seen the 94-98 MBs listed at both Monster and USA Spec to run the interface to CD Changer input. I'm sure you could do some kind of aux line in on the older Beckers, but you'd still have to control the iPod (selecting songs, tracklists, etc.) using the iPod instead of the had unit.

Hopefully the holidays will yield parts of this solution - I'll post next week whether or not that happens, and any related trials and tribulations trying to get things installed.