Heehehe... No problems!!!
Only the Letters from Iwo Jima is dual format, Unforgiven is straight HD-DVD.
I had had the same thought myself with 'letters', but when I direct HdBrStreamExtractor to find the files they are in the /HDDVD_TS/ folder, the same as the other HD-DVDs.
Then it shows all the different streams: Main Movie, and the extras, and when I hold the mouse over the main movie stream it shows 1080p vid and audio (whatever it is, can't remember!), but when I try to retrieve the individual streams from the main movie, it doesn't work at all, it also does not work directly from Eac3to (with the Eac3tomoreGUI).
Cheers.