Allow for variables to be set in admin to enable CDN usage for video or images.
On a similar thread, why not allow other images and scripts to be loaded from a different domain to increase the number of requests allowed. A subdomain (for example) for images, one for scripts (CSS and JS) and the main content can increase requests from 2 to 6.
CDN use is a big idea. At the moment I do this but I have to update core every time a new version of WP is released.