The only problem I see with a colored dome, is the dome does not completely seal the light from the flash tube. This means you will get 5600K light mixing with +/-3400K light. This makes a sickly color.
The gel application in the video (which is very cool) is a bit...hastily engineered. Rob Galbraith has a similar set up, but applied in such a way that seems more durable.
http://www.robgalbraith.com/bins/imageR.asp?rim_id=3569 I have also seen where a "C" was cut from a gel, which then would wrap aorund the speedring cage.