
Frustratingly,
David

David,
Have you ever checked into either JQuery or Moo Tools? Both are pretty awesome javascript / ajax frameworks. With those, many developers have written scripts which is under the GPU license that you can use in conjunction with those frameworks to achieve all the things you're talking about. What's even cooler is that most of the scripts give excellent step by step instructions for how to integrate into your site. Just do a search for anything you may want like "JQuery Photo Gallery"... or "JQuery Accordian" and see what pops up. You'll be pleasantly surprised with all the options. As a guy who has also developed themes for WordPress, Joomla, and RapidWeaver; I can tell you that most of the templates you see do include the very same scripts that ride on JQuery or Moo Tools.
As far as the menu on the Web Assist site, it is possible to do that with CSS Menu Writer... but you will need to get the basic part of the menu done first and then customized the html in the various lists. In fact, I am working on a site for a radio station that was inspired by the WebAssist site and I have been able to make the menu do exactly the same thing and look nearly identical just with WebAssist tools.
Cheers,
Brian