...your dad should be able to engineer/ construct an el-cheapo model simply by looking at the mounting space dimensions, cd player exterior dimensions, mounting locations, and wire/connector lengths.....no problemo- - its not rocket science

otherwise, you could probably source one from a MB boneyard for $10....or less if this is the price you want to pay....

another option is to stop by the dealer and take a look at some used MB on the lot....

even with the dimensions provided, he'd may still need to envision plans using step 1 above

-fad