I wrote about this in the anime downloads thread but didn't get any clear answers. From what I have found there are 2 OVA:s, "Memories in the Rain + 13 Squad Omake" and "The Sealed Sword Frenzy" (http://www.animesuki.com/series.php/496.html).

The thing that boggles me is that I can't find any more info on "The Sealed Sword Frenzy". Is it in production or doesn't it exist at all?