IIRC in conversation at EA Global the maker of Speciesism said the total cost of that film was <$100,000 US. I believe he said he was in the process of making another animal advocacy documentary but I am not sure.
Probably also worh noting that:
There’s preliminary evidence (p.23-25) that documentaries could be one of the most effective diet change interventions.
I think Faunalytics is currently considering some type of evaluation of the effect of a documentary on diet.
There’s could already be an adequate supply of animal advocacy (excluding WAS) documentaries. It’s could be better to instead direct resources to promoting existing documentaries rather than funding additional documentaries.
Daniel Irving is currently making a documentary about EA. Little unsure of the specifics involved, but he has interviewed a number of EAs.
There has been some criticism of the accuracy of Cowspiracy's facts - ie. 15% of emissions instead of 51% of emissions as claimed. I think it is important to be aware of this, because if Cowspiracy is used as an outreach tool, then it might damage our credibility (especially given that the name makes it sound like a conspiracy theory).
The larger point---that film can be a compelling vehicle for important ideas---stands regardless whether Cowspiracy was fully accurate or unbiased in its selection of figures.
That said, I agree that we should be cautious about endorsing Cowspiracy in particular, since certain key numbers on which it rests its arguments and emphases are disputed (good discussion and links on wikipedia). That said, it's a bit unfortunate if discussion surrounding the film centers only around fact checking--e.g., 15% vs. 51%--when in most any case there is an important, oft-overlooked environmental rationale for a shift toward cutting livestock out of the world's food system.