The Droid X has a screen an audio system of its own, thus it already provides support for personal viewing. The HDMI output is effectively adding a second playback device and since the HDMI output is a digital signal that likely gets into all sorts of Digital Rights Management and HDCP issues. So there may be two aspects involved in getting some of the sources noted at the HDMI output, one being whether the DX hardware can support HDMI out for HDCP protected media and the other being if there are legal rights management issues regarding what can be available at the HDMI output. I don't think that these aspects would be addressed by Motorola or any of the content providers, or necessarily legally by anybody, at least without additional expense and/or fees.
And to be clear, I am not trying to take a stance on copyright, HDCP or digital rights management, just pointing out that these are likely a factor in what can be displayed on the Droid X HDMI output.