Thanks for your insightfull narrataion! OSS is about community, it is built on your enthusiasm, feedback and contributions.
I also understand the difficulties of being the middle man between "non-technical administrators" (decision-makers you mean?
I hope, I'm allowed to comment on a few things as a non-developer.
- Your initial problem was about the documentation for MS propriotary systems. You must understand that most of the Moodle developers work on some sort of a open plattform (Linux, *BSD) or an almost open one (Solaris, Mac OS X) for obvious reasons. Being notorious enough for not documenting on their native plattforms you can guess the state of documentation for "alien" plattforms.
The way out is simple: People like you, who are native to those plattforms must take a dip and document it for others!
> "Open Source software is rarely very difficult to install. You needn’t hire additional staff for that purpose, so, in fact, it doesn’t really represent a shift of money from Purchasing Software to highing IT staff."
Who told you that? This is IT: No input, no output! In my view it is about employing local staff rather than sending money out, it is about building know-how, it is about investing on your future, it is about freeing yourself from the propriatory lock. If I may use an unfashionalble word, it is about freedom!