milkandhoney, are you willing to look at a "seriously" hacked version of your html? I think the bugginess can be worked around by changing the structure, but it's early yet <smile>. Obviously, it will not be a plug-n-play fix. Just an example of how to change the widths and table layout to make it work in spite of Microsoft... which means, you'll have to adapt and style my hack to work with you cms <smile>. I'll give it a try if you're interested. Your structure as indicated by the comment marks will be altered.
If I use a bit of css, will mailchimp turn it into in-line code for you? (I've never heard of mailchimp, sorry.)