@gevik we are looking for a tool similar to this and it looks like what you have done would be, at the least, a good starting point for us. I understand you have moved on to other thing; however, we are interested.
Unfortunately the code is not in my possession anymore. But what I can disclose is the following: The ExtDiagram was/is based on an adaptation of the http://diagramo.com. You can license it from diagramo, and try refactoring it into an ExtJS View. You will need some matrix calculation knowledge (if your math skills are rusty). I hoop this helps and good luck to you.