Now that I think about it, some PortableApps.com applications do that.  See http://portableapps.com/apps/internet/miranda_portable for the first example I found that did it.  I propose then that we add in another such line linking to http://inkscape.org/donate.php and merge into it the contents of http://wiki.inkscape.org/wiki/index.php/Inkscape_Wiki:Site_support, and add a menu item to it on the site as well.  Which is the "preferred" or whatever donation method?  I note that US$25,000 is the maximum the Google Checkout one supports :P

Josh, I'm sure you can cope with copying and pasting a line of HTML and modifying the text in it, do what you reckon :-)