An approach to dominating a niche I am wondering about?

I have been discussing various topics regarding how to get higher rankings at this and other forums lately and have been wondering about one approach that I would like to use but am not entirely sure about.

That approach is this...

You have a web site. It ranks sufficiently high that you are getting some traffic to it. Not much but some. You are on page 2 of Google for your targeted keyphrase for the home page and are showing up in various positions for long tails.

You see the stats and notice that some people are finding you on page 2 or 3 of Google for related phrases that you are not targeting. This is commonly referred to as long tail traffic which in some cases can amount to 70% or more of a sites traffic (though it comes in through long tails that do not in and of themselves have sufficient traffic on their own to make them worth targeting).

If I see a small cluster of long tails coming in and that my site is apparently ranking for (to some degree), get a really high quality article spinner (like the Best Spinner not the garbage one's), spin my home page, and build additional pages with some tweaking to now target the long tail phrases that are appearing in my stats.

Has anyone ever done that and if so how effective was it in increasing the traffic to your site as more and more articles started ranking for more and more long tails?

I would also interlink the site pages by creating text, keyword anchored text, links between the pages.

The downside I see is that if a human reviewer looks at my site he/she will see that most of my pages are about the same thing only said in a sufficiently different way so as to avoid duplicating content with a minor paragraph added here and there to better target a long tail but still...essentially the same thing said over and over again on different site pages.

Thoughts on this approach would be most appreciated as to whether or not it s worth trying and whether a human reviewer might discount my site and penalize it for being duplicative in spirit if not in actual practice.

One could easily develop a site around a specific keyword phrase this way and end up with a hundred pages all focused on the essence of the site keyword phrase. I don't know how effective this would be so I am asking before I move forward any more with this idea.

Thanks.

Carlos