Anyone who uses Firefox for specific apps might be interested in this product from Mozilla Labs, PRISM:

http://labs.mozilla.com/2007/11/prism-prototype-now-available-on-mac-and-linux

It enables a single window display of the app (url) you select, saves it as a shortcut so it can be run like any other app and drops all of the screen detritus associated with the browser. I started using it over the weekend for Google Mail, Calendar and Docs and had no problems. Enjoy.