The University starter kit Mark mentioned is indeed a great place to start, just keep in mind the glitch they have (scale the window till it snaps to mobile, click browse. click browse again and then make the window bigger again... think portrait/landscape orientation switch).
Brad Frost has put together a blogpost regarding 'responsive navigation patterns'
with dozens of links to each best-practice. One of them mentioned is the Filament Group
, they have a great step-by-step tutorial on how to go from regular <ul><li> to a responsive menu.
On the forums here, several snippets are presented as to how to render the Sitefinity pages as a clean <ul><li>:
by Aptera in the Marketplace.
by Rein, another one
by Brandwidth and one
by Josh Morales.