Mark Call fairly politely responded to my request for Biblical evidence supporting his position that polygamy is not inherently immoral and against God's law... and I have to say that I am convinced now that he is correct. If it is not in scripture, then it's usually better to assume that God did not intend it to be that way. While I do believe that God is not fond of polygamy, the key issue is the intentions of the man who takes multiple wives. A good man, a man who intends to provide for all of his wives and isn't forcing them to live far less than they would if he married only one is not going to bring the wrath of God upon him because he is doing what is fundamentally right: caring for his wives.
Regardless of whether or not polygamy is compatible with the Bible's standard of marriage, the church ought to be highly skeptical of any man who wants to take more than one wife, especially today. I would personally never go to a church where men who wanted more than one wife went unchallenged by the elders and pastors. That, and the church ought to insist that any such man prove that he is capable of providing for all of his wives and children.
So, to put it bluntly, the Levirate law in my opinion is enough to settle the question when combined with the fact that nothing in the New Testament explicitly says that a man must not marry more than one woman. While I do think that Mark 10 shows a clear preference for monogamy, as that was God's original plan, I think that there is room for the church to bless a polygamous marriage if it is more or less sought for holy reasons.
Fascinating.
I do believe that God intended for it to be a one to one thing. Period. But He always makes allowances for us. Talk about forgiving.