The data storage editing features of core game entities has been completed at a rudimentary level with the new architecture and I am now working on a map browsing feature with which to visually edit game content. I'm experimenting with embedding a 3D graphics engine (OGRE via a previously graphics layer code) into the editor, but if this proves too much work - it shouldn't be, but you know how these things are - I might look at a windows GDI solution.
I will post updates as they happen. Right now, it's not particularly enthralling news, but it's nice to be making progress!