How To Customize Current Navigation (Left Navigation) in SharePoint 2010 To Show Multiple Levels?

What?

SharePoint 2010 has a limitation that it only shows up to 2 levels of navigation items at any given time in any page in the current navigation (aka current navigation).

Let us take a typical scenario where I have my site structure as defined below:

Root site
  Team Site
  Subsite Level 1
    Subsite Level 2
      Subsite Level 3