Get ready HOTD English fans because, Sentai Flimworks has just announced that they have they have acquired the license OVA and are streaming it with a English dubbed version of said OVA, while it has no effect on the manga hiatus its something from the HOTD world which is better than nothing, currently this is no release date but I can only hope its coming soon.
Official Source: http://www.animenewsnetwork.com/news/2012-09-29/sentai-filmworks-adds-highschool-of-the-dead-video-anime-streams