ok finally got around to looking at this and here's the 411..
there is a very easy solution to integrating your ipod with the factory mcintosh head unit. you'll still have full six cd stacker function and this is hardwired, not fm modulated so it should sound better.
mcintosh is owned by clarion (i'm pretty sure) so we sourced a clarion EA1251 CeNet iPOD interface. About $200AUD / $100USD go google it.
pull out the head unit. on the back you'll notice a black CeNet cable connecting the head unit to the cd stacker, remove it.
my EA1251 came with a Y CeNet cable ( part no. CCA-519 ) but it may be optional so make sure it's included or that you buy one. it also came with a CeNet cable to connect an ipod to it.
first, the Y CeNet cable - plug the single end into the head unit CeNet plug, plug each of the other two ends (the split cables from the Y cable) into the cd stacker and EA1251 respectively.
second, the ipod CeNet cable - plug the black CeNet end into the EA1251 and the white end into your ipod.
now the fun part, turn the head unit on. you should see a clarion logo come up on your ipod.
to access the ipod and listen to it's treasure trove of audio goodness, you just need to press the DISC button on your head unit ( bottom right ) the DISC button is what you use to switch between iPOD and CD Stacker
once you press the DISC button you should notice a CHR or CHG light on the top left of the head unit display. this means your on iPOD input. funny how they don't use CHR/CHG for the oem stacker but anyway...
ok now you're on iPOD input as opposed to cd stacker input, you should hear some music playing from your iPOD. if you can't hear anything but can see track 01 playing, then you either need an iPOD firmware update or you're using an ipod not supported but most models are supported.
here's the weird part...
when you're in CHR/CHG iPOD input mode, your disc access buttons become very important (1-6 under the display) when 1 is selected the head unit will play every frickin song on your ipod from the beginning of the song listing. when you select 2,3,4,5 or 6 the head unit will play playlists (up to five) from the beginning of the song listing.
playlists... in itunes you need to create up to five playlists and label them clarion1, clarion2, clarion3, clarion4, clarion5 and clarion6 otherwise the mcintosh headunit won't recognize the playlists.
the left knob will fast foward/rewind the current song or skip the next/previous one just like it would on a cd. the steering wheel controls work as well.
because you're controlling the ipod from the head unit, there's no need to keep the ipod anywhere in sight.
no it doesn't recognize ID3 tags or any text info, all you'll get is a track number (up to 99 from what i can gather) and the playing time, just like a cd.
it sounds great and is very easy to install. takes about an hour, most of which is pulling the gear shift facia apart.
no you don't need any blank cd's, you get full six cd use like you've got now.
err, that's all i can think of. if you got questions let me know.
pics? yeah i've got some but they're on my phone and i'm using my girls ibook - too bad so sad for you. i'll post em later (not that there's much to look at)
hope that helps