Konstantin Obenland

This plugin enables the showcase template automatically slide through all the sticky posts. 
It simulates the mouse click that triggers the slide change every four seconds.

Twenty Eleven Showcase Slider

Adds carousel functionality to the Twenty Eleven Showcase slider.

Rafa Poveda

Mecus Consultores

Rocio Valdivia

This plugin moves the default Twenty Eleven menu via CSS to the top of the page. 
It adds rounded corners and respects the header image.
The plugin is intended for only-image headers, without text, to show them a bit prettier.

Upper Menu for Twenty Eleven

Moves the default Twenty Eleven menu to the top of the page with a nice CSS.

Twenty Eleven Showcase Slider vs Upper Menu for Twenty Eleven