Video cabling and interference

Does anyone know how susceptible video connection cables (component, S-vid, DVI) are to interference from running inside a steel tube? Maximum parallel run would be about 4', so I don't anticipate a real problem.


By way of explanation, I am currently driving myself nuts trying to design my own stand for a plasma I don't have! (Must be the engineer in me!) I'm currently working on a design somewhat like the Samsung "Captain Kirk" DLP pedestal (althought substantially simpler construction, and with media shelves) and I want to hide the cables by running them inside steel tube or channel. I'm fortunate enough to work for a manufacturing company and can buy material at cost. A little cash to the welder, do my own grinding, about $100 for powder coating, a little more for some shelves and I figure for about $400 I'll have a pretty cool stand that will support all my components and the plasma. Saves me the cost of a wall-mount or table-mount stand, and I need component shelves anyway.