OK this post is from Ian Cylkowski aka izo.
please please have a look!
http://www.design-by-izo.com/2010/02/27/deconstructing-nautilus-and-rebuilding-it-better/
It shoes some nice mockups

So if someone can link me with a tutorial how to extend the nautlius sidebar I will add the "commonly accessed" functionality within an hour or 2!

PROMISE