Unity, please, comment your DLL code and export the XML Document file, like Microsoft does for its libraries. It would save me tons of time wasted in googling the proper type and method.
Due to the way the docs are produced and managed, we probably won't produce XML docs directly from C# in the traditional way. However, our XSLT-based generation system can certainly produce Microsoft-style XML docs as an output format. We've already got that down as a task (lots of support for going some way back as you can see here) and so it's just a matter of priorities relative to other requested features.