Real HDMI app brings full HDMI output to Motorola DROID X
Now there is an app called Real HDMI, which costs $1.99 on Android Market, that claims to resolve the issue. It is allowing you to stream the said videos through, as well as show whatever your phone is displaying, on a larger screen.
User reviews are quite positive, and there is a Q&A what works and what doesn't in the app description, so if you need full HDMI on your DROID X, you can head over there, and give it a try. Bear in mind that it fully supports only the official ROM for now.
Motorola DROID X Specifications | Review