Jon Lipsky has been doing some wonderful work on a Confluence client recently (see his blog entry and the XMLFace examples page for screenshots and webstartable versions).
Although primarily intended as an example of using his companies' XMLFace library (an XML gui definition library which allows you to generate Swing and SWT interfaces) it is actually quite a useful Confluence rich client. It doesn't yet have TimTam's sexy tree view, but it does work with Swing (albeit with an ugly HTML renderer) and support searching across all spaces - neat!
Does anyone have an updated link for Jon's tool?
I started looking for this a week ago and the site has yet to be available.