Cactusdaves image at
http://www.photomacrography.net/forum/v ... hp?t=16225 and the further discussion at
http://www.photomacrography.net/forum/v ... hp?t=16250 (and having my name mentioned!) prompted me to have a look at my own slides. Unfortunately the mounts I have are quite thick, limiting my chances with a x40 objective. There is some hint of 3D structure visible using a x25 Leitz ICT (DIC) objective. Here is a stereo pair, which may help in visualising the structure:
Unfortunately, not quite as clear as I'd hoped, but perhaps someone else may be inspired to try something similar.