Ben,
Ask your Netapp sales rep for a demo installation of DFM (Data Fabric Manager) 2.0. Once you've seen it, you'll find a way to buy it.
DFM 2.0 runs on Win2K or Solaris and can scale to monitor hundreds of filers. It has a CLI interface which can be used to manipulate filers, but it also provides nice-looking graphics for you to show to management (i.e. disk space trending, etc).
/Brian/