So it turns out I know not of what I speak.
I mean yes, technically BD9 and HDDVD9 are spec standard... but there's really no way to make them yourself.
I believe you could with stuff like Nero Vision, but if you want to use x264 codec and do it by hand it's not really possible yet.
NDAs prevents detailed information from coming out.
There are custom profiles under MeGUI
http://forum.doom9.org/showthread.php?t=101813&page=1 that are experimental for HD-DVD, but it's just that: experimental.
I'm not sure I feel good about taking a project and leaving myself at the mercy of crapware like Nero Vision.
I'd really like to not have to do my project again in a few years when the formats shake down. But on the bright side by then we'll all have HAL computers with 8 core processors or something.