Network topology

[karnaugh at karnaugh.za.net (Colin Alston)]

Hi all

I'm considering trying to come up with some means to automatically 
detect a networks topology and draw pretty pictures. This is somewhat 
boring though if a network isn't well arranged with VLANs and q-tag 
trunk routers and so on (It will just look like a big cloud of junk 
connected off an assumed switch).

Is there any kind of cunning trick to detect standard layer2 switches 
along a path without stuff like STP?