Hey!
Dude is right, we will probably not add this because of the similarity to Replete and because I dont want an option overkill :)
There is however a quite easy way to get a similar result to replete:
add this to your custom.css stylesheet in folder /css/ or to the quick-css panel located in your wordpress backend at choices->styling:
#top #slideshow_big .container{width:100%;}
Once that is done you might want to open your functions.php file and search for the image size array at the top. increasing the size of the featured images (especially the width) might be necessary depending on the screen resolution of your target audience :)
Its not perfect but its at least something :)