One thing that I have not found anywhere is a ‘fluid/adaptive’ slider that works on sites like twenty-eleven.

If you build a fully fluid template then everything must be % based with no fixed images/videos etc. (Anything fixed will break fluid column layouts)

Every single slider on the market requires a fixed width to be set in order to function.

I did manage to build one myself that works pretty well, but it is very basic. I am guessing that as more and more people start to use fluid themes with css3 media queries, that the demand for fluid sliders will only increase.

*Warning*
This is NOT an easy project and it requires pretty decent math and js skills to pull off.