I have a indoor music festival coming up that uses a massive amount of LED. The production designer wants a motion background with a pipe-work of VersaTUBE on top. The production doesn't have the budget for all the custom framework it would take to do the VersaTUBEs.

So, my question, if the whole set is a 30 mm LED wall, what is the best way to make it look as if their is VersaTUBE-like piping on top of the background?

I was thinking perhaps a 3d model of the TUBE layout, or video with an alpha channel. Any suggestions or advice?

Rendering the content with the piping is not an option, as there will be need to treat the background and TUBEs as independant systems.