Finally tracked down what was whacking my Ozh' Admin Menu in sub-directory sub-blogs in Mu. If the Use Google Libraries plugin is activated, whether site-wide or individually, the CSS fails to load. I suspect that it is due to this from the UGL readme:
In general, anything that calls wp_eneque_script before 'init' will stop **Use Google Libraries** from loading.
which then prevents the admin menu from working as it should. The libraries themselves are the same version: 1.3.2., and looking at the loaded Javascript with Web Developer shows that they are loading but perhaps not loading early enough.
I looked at the code to see what the above meant and perhaps find a workaround but am unsure enough about the 'init' line that contains wp_enqueue_script("jquery") function that I left it alone and decided to ask.
http://wordpress.org/extend/plugins/ozh-admin-drop-down-menu/
