Well, after much conjecture, I've decided to start the first release of this in ASP.Net/C#. This is mainly because most of my experience has been in Win32 programming, and I wanted something at least slightly portable. I've just about finished the specs, which I'll post here too, and have started drawing some of the application flows.
The project was approved today by SourceForge and I'm getting documentation ready to post for this project. Soon I will also have a shell of an app submitted as well.