Metadata in the MetaWeblog API

Phil Pearson is trying to send extra data over the MetaWeblog API. First you have to find (or make) a tool that's able to let you input and send the extra data, then you have to find (or make) a CMS that reads and stores that extra data, and then you have to find (or make) end-user tools that are able to do something with it. It's not easy (is it's possible at all).