@ Andrew Barnet, I haven't tested this, but it should be possible to address the top-level page only, by making this a chrome style and finding the parent element of the page, i.e. the browser.
This is nice, except that when opening a page chock full of frames or iframes (e.g., any online banking page, an online shopping page like safeway.com, etc.), you get the about:blank label all over the place, which looks hideously ugly. Could it be changed to only affect top-level pages?
BoffinbraiN said about about:blank label on Feb 25 2008
Andrew Barnert said about about:blank label on Nov 13 2006