I was trying to create a menu based on your plugin but using background images assigned with unique_class
through css (instead of text).
I modified your plugin and added link_wrap
parameter which allows me to wrap links into tags like this: <a href=""><SPAN>navigation link</SPAN></a>
and then set #nav li a span
to display:none.
Some better way might be to actually display the images somehow (might be more SEO friendly ?) but this is just an idea.
Anyway this is really great plugin!