3X DVD is a red-laser DVD standard that works on HD DVD players but uses standard DVD discs rather than the more expensive HD DVD disks. The discs, which are now available, offer AACS copy protection but transcode video to VC-1 or AVC and lower the resolution to 720p, not bad, but definitely not great.
This sounds sort of like the VCD standard — popular with pirates but not with anyone else. It still technically offers HD content — albeit considerably downgraded — and the discs and burners are currently prohibitively expensive for the average user. I predict this will be an “also ran” standard that appears only occasionally and in the shadier corners of the media ecosystem.