If there are some pages you want to hide the quicklaunch to gain that little extra real estate, then there is a really simple fix.
So the simples way is simply to hide the Quicklaunch using CSS. Actually it hides the entire area the Quicklaunch is placed in, and gives you access to the whole areas width.
Simply add a Content Editor Web Part to the page and edit it with “Source Editor”.
Page the following:
You can also just hide the actual Quicklaunch if you want to place something else there: