Custom Component Variable Size(s)

Something I’ve always wanted to do was creating a custom component in Flash but have specific parts of the component size appropriately based on, say, the video size.

For example:

tv.adobe.com - go there and watch a video… they use the same component for all sizes of video. What seems to be changing is the video width and height, the progress bar width and the position of any status messages for the video.

How can I create a component that will scale properly and keep things in place? And without any anchoring options in Flash, how can anchors be created?