Your demo link is 404 but from the Barenakedapp.com link i see what you mean. Actually in Google Webmaster tools, the Pagerank for High, Medium, Low and Unassigned are presented like this.
So a nifty trick is to view the source and you can see the Green Bar for High is 18% for example. If you have 100 pages, you can conclude 18 pages currently have a high PR despite what the old toolbar values state.
There are a number of other sites using this method, so you can get some specific data instead of the presented graph with a progress bar "yay" long.
I always used to use two <div>s, overlayed ontop of each other, one with 100% width and the foremost with 0%, and just increase the % value as required. This method looks nice though.