Taxonomy Browser display as nice menus?

Hi,
I was wondering whether it is possible for the category browser to display only the highest level of the hierarchy (e.g., continents). Only when the user hovers over a particular category, the menu then expands the second layer (e.g., hovering over North America then reveals another menu (or radio boxes) of only the appropriate countries, and so on down the hierarchy). This would be similar to the effect of having the nice menus module with primary links. I need something like this to limit the clutter that would otherwise occur with a large taxonomy.
Thanks for any advice.