Torture Test--Is this asking too much of the browser vendors?

I'm working on a forthcoming issue (on how well browsers deal with
standards) of an e-mail newsletter I write for the computer-aided design
industry, and though the article isn't quite done yet, I have created a new
layout and related pages as reference material to demonstrate their use and
how well browsers support them.

The newsletter won't hit for about a month, but since I'm doing a few things
that are pretty radical, I'd like to make sure I'm not doing things that
just shouldn't work, I'd like to solicit feedback on what I've created, lest
I have to issue an embarassing correction to our 30,000 readers because
I've created something inappropriate.

I decided to try nearly every bit of HTML and CSS I'd always wanted to use,
but couldn't because it didn't work right--especially fixed positioning, so
it provides quite a workout, even for Mozilla and Opera.

http://www.cadenceweb.com:8080/newsletter/sheerin/webstandards/

So try it in your favorite browser, and let me know what you think of the
challenge I've set out for the browsers. Have I gone too far? Not far
enough? Are there significant things I've failed to include?

Because I'm trying to set an example, and use these pages as a sort-of
browser test, I don't really care how well it degrades in older browsers (in
fact, it only really works right in Netscape 6.2+, and at least one thing
won't work until Mozilla 1.2 progresses a little further), but I'm
interested in any and all comments on the design, how it works, or my
assumptions.