First of all, I want to say that ZCS is a very impressive suite, especially for a beta. To be honest, though, it is the AjaxTK which impresses me the most.
It occurs to me, however, that it should be possible to wrap the DWT and other objects in JSP tags, which could then be used in any JSP authoring environment. I was able to do a small proof-of-concept for this in a few hours this evening. In addition to making it possible to use the toolkit without writing script, I think it would be possible to create XML databindings this way. Are there any plans to provide such a tag library for AjaxTK?
The AjaxTags project (http://ajaxtags.sourceforge.net) is something like this, but the actual control set is very limited and not as visually attractive as AjaxTK.