A Professor of Classics at Mt. Holyoke College has just published a 96-page commentary on the Melian Dialogue in the same format that is used in the volumes on this website. The book is available in paperback for 8.95 USD on Amazon (link).
I recommend this book to anyone reading Greek at the intermediate level or above and hope that teachers of ancient Greek will consider using this inexpensive commentary in their courses.
If you consult the “Look Inside” search function on the Amazon website, you will have full access to the introduction, bibliography, core vocabulary, and a few pages of the commentary itself.
The book is well worth a look.