Here's how they should cash in on Fate/Zero when it is all said and done:
Fate/Justice - 26-part original TV series about Kiritsugu's adventures in the 10 years or so leading up to Fate/Zero. Features Kiritsugu on various episodic missions, sometimes with Maiya, sometimes alone. Serious and bleak, but with various plot twists and tons of action along the way. The series should tie into the start of Fate/Zero by the final episode, and is meant to directly appeal to fans of Fate/Zero.
Fate/Conqueror - 13-part comedy/drama series featuring Rider and Waver's adventures in shopping and chilling around in the house, mixed with serious flashbacks of Rider's past life. Every episode is built around a hilarious situation which Waver finds himself in, and only Rider's experience as King of Conquerors can help him out of it. In the end of each episode they both summarize the lessons learned to the audience.
Fate/Talk - 6-part hour long OVAs featuring Gilgamesh and Kirei sitting around drinking wine and having long conversations about various topics. This unorthodox series is targeted at adult men and obsessed fangirls. Each installment will cover a range of diverse topics ranging from film, culture, music, politics (from the 90s and before), etc. Gilgamesh will critique these topics while Kirei describes them in matter-of-fact ways. Each topic is paired with a specific wine, which is also part of the critique.