This thread isn't used anymore, I opened EQInterfaceArchitect thread for it since this one got kinda long. Send me a pm with your email address if you'd like a copy of the source, but keep mind of the very basic license I put in all the code files. The library files are actually usable now to load the xml data into C# code classes, even edit them, I'm working on the visual stuff now and the editor itself.
The library could at this point be used to make a text based editor, or your own visual editor, I have no beef with that, like mentioned it's been designed to be that way, only requirement is .Net & XNA if you want to leave my rendering code in for the elements I have done. Just if you comment out my XNA rendering stuff be sure to make note of it in the license headers of the code files you do it to.
You'll need Visual C# to open the project file, or you can open the code files, .cs in notepad. Visual C# Express is free from microsoft, it's the C# programming tool without all the fancy tools of the professional edition, really I've never used the professional edition for C# so I have no clue what's all in it, the basics are good enough for me. You'll also need the XNA Framework to compile it.
Visual C# Express
XNA Game Studio Express Refresh 1.0
Install C#, let it update, install XNA, open the csproj file, view the code or hit build to run it.