What about the History Channel? They could make a documentary on Rabbi Kahane and the rise of the JDL movement and campaign to free Soviet Jewry. I think that would have sufficient interest. Not only was it an important historical Jewish movement, but it also is significant because it would deal with civil rights issues around the 60s and 70s such as affirmative action, violence, relations with blacks in the city, civil rights, etc. It would be an important documentary about American history, not just Jewish history.
I think in the end it would be too controversial and politically incorrect for any of the cable networks.