A Moodle course? I just ran across this software and was thinking about using it for a Beginning Greek class I am teaching this year. Sounds interesting.
While Perseus gives the text and one can download the vocabulary, the Perseus vocabulary list is just a 'guess list'. Each specific word in the text is not pegged to the correct lemma - Perseus does have a rating option which lets people select which lemma they think any specific word comes from. If Perseus is robust (i.e. does not have excessive down time -- it is Summer, and few Greek/Latin neophites are using Perseus), this would be a good way to share the reading groups contributions with the rest of the internet world. In other words, if those in the reading group peg the words in the Discourses to the correct lemma on Perseus' reading page, more long-lasting results could be acheived.)
On the other hand, I would be happy to use an Access database to peg each lemma to the correct word - and then publish that to the web. I had (and still have this goal for the Enchiridion). Shenkl's appendixes are invaluable for the words and constructions used in all of Epictetus' writings. If Schenkl's appendixes could digitally converted, it would be a great resource for all who read Epictetus. (Perhaps in the future). But such a project is not needed for a reading group's success.
Schenkl's Appendixes can be downloaded from http://www.letsreadgreek.com/epictetus
So far it seems most of those people interested in reading the Discourses have a fair amount of Greek under their belt. So if we go forward, who will propose a reading schedule? How many words a day/week (or pages in a Loeb edition)?