While I appreciate the non-combative tone of these essays, there are several problems.

a) "There is a difference between what is described as taking place in the narrative and what the narrative endorses about the practice in question."

Do you not find it a bit curious that the most minor transgressions against the very explicit laws of Leviticus (in which there is no mention of polygamy) resulted in ostracism or even death (such as the man gathering firewood on the Sabbath), but Scripture leaves it up to subtle narratives and plot lines for us to gather that polygamy is a moral evil? You can suggest anything you want, of course, but this is hardly reasonable.

b) "[T]here is something problematic allowing shifting civil social standards to dictate the defining of moral standards or the interpretation of religious standards."

Certainly, the Bible and religion are useful in terms of how they influence our moral sensibilities. The fact is, however, that Christian societies have always and can only extrapolate the moral standards defined in Scripture using the interpretive lens of their own time and place. These views are often colored by the secular ideas of the culture of their time.

When the majority of people believed slavery was not a moral evil, well, Scripture conveniently agreed (see the essays of Thornton Stringfellow). When it was not a moral evil to use physical torture to "convert" unbelievers, it was used by Christians as a useful tool (http://www.biblestudying.net/johncalvin.html). Ask someone in 1955 if interracial marriage was not only distasteful but immoral, they would probably agree, and they would invoke the name of God and the Bible to buttress their own beliefs.

There may be a "true interpretation" of Scripture. Unfortunately, no one's really going to know what it is, because the authors are no longer among the living, and the confusion that has been passed down over 2,000 years remains as witnessed by the countless arguments and disagreements among Christian denominations (even orthodox ones).