Somebody told me a few months ago that PDL were bringing out a 500/600 series HDMI module for their faceplates. I haven't personally seen one but there would be no harm in ringing your local electrical wholesaler (such as Mastertrade or Corys) and asking if these are infact in the marketplace yet.
Thanks Steve, I have asked them this morning via their website but will call them as well. That would be the optimum solution for me as I use the 600 series now. Just mounted the LCD on a Sanus bracket and want to hide the cabling.