I have problems making this setup work. The hitachi ld6600 has a resolution of 1366*768.
dvi: when I connect with a dvi-hdmi cable, I get a nice picture on the tv, but it is 1280*720 with black borders around, offset to the top left of the screen (before I turned off the overscan a great deal of the desktop was not visible). hitachi support told me that the problem was that my mac-720p was not the same as hdtv-720p because of different sync-signals, and therefore the tv does not really recognize it and scale the image up to 1366*768 (but it says it is receiving 720p). they could not tell me what timing is correct, though. yesterday I registered displayconfigx and tried setting up my screen. I chose the hdtv720p preset, and this time I got a picture that filled much more of the screen, only a tiny black border on the right. Now it looks like the overscan issue is back, though, and the options tab where I can turn off overscan vanishes when I install displayconfigx.
vga: I have also tried connecting using the dva-vga adapter. when I start up I get the bootscreen, but after a while the screen goes black and says 'out of range'. I tried again after I had installed displayconfigx and set the parameters of my tv (allowe refresh rates, resolution), but the same happened, and I had to boot in single-user mode and delete the display mode to get picture back on dvi/hdmi.
I'm running out of ideas here, so I hope someone can help.