I had an email in response to my last post from "Manu" at www.tideway.com ...
"I would say you should also consider evaluating non-framework related solutions like the ones from Ni2 or Managed Objects (I am not working for either, so this is impartial feedback from our customers).
This said, I personally think that evaluating CMDBs without the tools that populate them is limited in value. .."
The plan was to investigate the three products named (each claiming to be an industry leader) along with their respective discovery mechanisms, but I hadn't explicitly stated that, so good catch Manu!