In the past, I have developed the MINI circuit and some iBus protocol things including the HKenabler and a circuit to send MFSW button signals to an iPod remote.
More recently Dension has been developing an ICElink Plus which allows an iPod to be connected to the MINI stereo, controlled from the MFSW and (promised for one day) track info displayed on the head unit. Unfortunately, there have been some early problems.
Today, David Broome (who I have chatted via the Yahoo HackTheiBus forum) announces success with displaying text on the MINI stock radio:
Read more about it here on MINI2 or here on Davids web site