I absolutely love this idea and am amazed that it isn't common place amongst webmasters.
Although - and please don't take this the wrong way - I do have one small grammatical error to point out about your article as it really confused me for a moment. When you write "How to redirect to www from non-www version" and "How to redirect from non-www version to www version." These two sentences actually mean the same thing - in both instances you are redirecting from non-www version to www version.
I suggest a small wording change to the second option - "How to redirect TO non-www version FROM www version." This will fix any confusion someone else may have and assuage my pet peeve!
Thanks again for your interesting and extremely relevant articles!