After much head banging against the web site, I've discovered a couple of things. I want to relate them here so maybe someone doesn't make the same mistakes.
I wanted a layout for my WordPress blog that had the following features:
* Header on top
* Three column layout, all of the columns stretching all of the way to the bottom.
* Footer always at the bottom, no matter which of the three columns was the longest on any one page.
* No CSS hacks
Eventually I ran across the solution. There is no solution. That combination is impossible.
Maybe someday the Internet architects and the W3C will get together a create a solution for this, but it hasn't happened yet. There is no standard that allows the above, and there is no web browser out there that can implement any such thing, mostly because the standard does not exist.
If you are willing to sacrifice one or more of the features in the combination I listed above, then your project might be feasible. Otherwise, forget it.
I am dumping the idea of a three-column blog and moving to a two-column blog. Then I am going to try and make the best out of the situation.
Sorry to be so stern, but if I would have read this basic message a long time ago, I wouldn't have wasted so much time.