Wow, soapystar, that's a great suggestion but a frightening one. When talking about internal links, where do you draw a line of over-optimization? I have a rather large site about an industry where we have lots of standards names as well as part numbers are repeated in great many anchors. Say, you have a part and then you have pages about installing it, testing, troubleshooting etc and you may have literally hundreds of pages with the part's name in the anchor. Actually, I think this used to be exactly what brought my site to #1 SERP for that part's name. So, now it turns around and bites my a..? Wow, man, I do see that possibly happening but that would be a complete disaster 'cause the whole site's navigation is based on this sort of somewhat similar anchors.
And just to clarify things: I don't buy links and don't sell them either and there are not too many outgoing external links from each individual page. There are thousands from the site as a whole but only handful from each individual page.