Xbox-Scene got a tip about the new Xbox 360 board supporting HDMI. The parolees at Kotaku don't believe it, citing Xbox-Scene forum posters and their "apeshit" denial over the eventual obscolescence of their first-run Xbox 360s.
We, on the other hand, aren't so sure. If the 360 were to someday get an eventual HD DVD drive—we're not saying anytime soon—then an internal HDMI port would definitely make sense. As HD DVD hardware prices fall over the years, wouldn't it make sense not to ship two drives with one box? So if B follows A, and A is true, what do you have? That's right, an HDMI port and a bunch of angry early adopters.
Of course, we'll have to wait a few years to find out.