My I-Drive controller unit went bad a few months ago. I did extensive research on the part and was able to pick up a used one @ Weber Brothers Auto.
Weber Brothers Auto ask for Greg 717-867-2151
It only cost $75 for a complete I-Drive controller and I didn't even need to re-code it. I spoke with a BMW tech and he said to just plug it in and see if everything works. Sure enough everything works.... B/c it is a used one from another X5 with similar options... Thank God...