UDF 2.5 support

I don't know if it does, but the company that has made UDF support on the Mac through its own software I'm sure would know the answer to that question, as this software offers better UDF support than has been made available through Macs in the past:

http://www.softarch.com/us/products/rdvd.html

Yes it does. It can read the files on an HD DVD. By that I mean they will show in Finder but you *can't play* them yet, not in OS X that I know of.

Yeah, I'm in exactly the same boat... the next steps are: HDCP compliant video drivers and software to decode the discs :/ I think VLC can play the content once it's decoded, but I'm having considerable difficulty getting the it decoded.