This is confusing, so here is a summary of what I've found...
The phatbox supports the Porsche CDR220 head unit, but does not mention the CDR32.
http://www.phatnoise.com/products/digitalmediaplayers/pn_phatbox.php?selectedMake=Porsche
The DICE unit has no compatibility information:
http://www.diceelectronics.com/ipod_connections.htm
Dension’s ice>Link Plus only supports pre-2003 CDR22 units:
http://www.dension.com/icelink_info.htm
Dension’s claims their ice>Link Gateway 500 will be available for Porsches at the "end of June". It has a MOST fiber-optic interface, but it does not mention which specific head units this will support.
http://support.dension.com/dension/icelinkgateway500.php
There is a rumor that someone (Becker? They make the head units) is working on an iPod interface for the CDR23, to be available "in the next few months":
http://www.beckerautosound.com/beckerboard/viewtopic.php?t=8