Nice picture, and a nice frog. I would check http://www.reptiledeopt.com, as they usually have a lot of mantellas in (as does LLLreptile.com). Don't know of anyone breeding them, but thats probably cause I haven't asked around lol.
I have 2.1 and just posted a message on the other forum regarding care of their eggs. I just got my first clutch from them. They are a great frog, much more outgoing then some of the other mantellas and darts that I keep. And they are lightning fast too! Mine seem to prefer less light than my other frogs, anybody else experience that?
Gorgeous frog, thanks for sharing the photograph. I'm always excited to see more people involved with mantellas, especially with species that aren't commonly kept like your milotympanum. Enjoy the frog,