For the purpose of this general discussion of the relationship between NPOV and textbooks, we should all dig up some texts and look for examples.
I used to teach freshman economics 101 at the University of Alabama, and I remember being frustrated at finding bias in the texts that we were using. That was some years ago, and perhaps a review of that text (which I still have at home somewhere) with an eye towards finding examples of POV that could be made NPOV might be useful.
Samuelson, in particular, was notorious about putting his personal judgments into the text as if they were consensus science. Had he been subjected to the discipline of wiki-editing, his text might have been much improved.
--Jimbo