I ran across a blog post from Suzanne Cook this past weekend that has been around for a while, but that has some excellent information about techniques for debugging assembly loading errors. I'm not sure how I managed to miss such a useful and informative post for so long (it was originally written in May 2003 - 3 years ago!)
One particularly interesting strategy that she describes is how to use the Assembly Binding Log Viewer (fuslogvw.exe) to pinpoint exact failures. I have used fuslogvw.exe several times in order to narrow down specific assembly load failures in Visual Studio 2005, and this tool helped me find several of the workarounds that I listed in my assembly load failure troubleshooting instructions.
If you're interested in learning some advanced techniques for debugging and troubleshooting .NET Framework assembly loading errors, I encourage you to check out this blog post.