Shogakugan just announced that due to production issues, the last three ovas of the Roberta's Blood Trail series have been delayed for around three months more.
It is now expected that episode 3 is scheduled for a January 7, 2011 release, episode 4 for a March 2, 2011 release. And the concluding OVA will hit DVD and Blu-ray on May 11, 2011.