Note: Interested in show a bar chart? Try Select Box Factory 2.1 for jQuery (Help Guide & Download)
Otherwise, see 2.0 below:
Welp, i'm finally done transforming the code to be usable as a tool if you have jQuery 1.2.6+. I've spent many a week trying to perfect this in various browsers, and compiling a help guide.
Please see this link for everything you need to know.:
Select Box Factory 2.0 for jQuery (Help Guide & Download)
(give it a second to load, i've added a ton of dropdowns and code for examples in an accordion widget).