I've been reading the Opera Lively book, which is a compilation of interviews. One of those interviews is Francois Roussillon, an opera video director who started his own label, FRA in 2009, after his firm, FRA, had been working for other labels. They also do/have plans to do ballet: he said, "[w]e want to release a ballet collection with the Opera de Paris. We want to release a DVD with the Ballets Russes. We'll have "Le Spectre de la Rose" [Weber], "L'Apres-Midi d'un Faune [Debussy], "Le Tricorne" [Manuel de Falla], and "Petrouchkha" [Stravinsky]." (pp. 247-8, Kindle ed) About 'Petrouchka": "We filmed "Petrouchkha" in 2009 and we did it in studio conditions; we had the possibility of putting the cameras very, very close to the action. It wasn't the kind of filming work that we do in the theater during a live show. It was really another way of working." (pp. 248-9, Kindle ed.)
When asked about the cost of producing a DVD, he said,
Well, the technical production cost is more or less constant. It certainly depends on the importance of the means utilized (number of cameras and days of filming) and the editing time which is also related to the duration of the work. But for the artistic rights it is extremely variable...It is difficult to mention an average amount. But a very gross estimate of the technical budget and the artistic rights might be established, I guess, at around half a million Euros. But this is an approximation that isn't very significant since the circumstances are so different from one filming to the next. [p. 341 Kindle ed.]
The artistic rights issues for opera and ballet are very different, since singers are, for the most part, contract employees, but it's interesting to note that the physical production costs are relatively stable, and some percentage of half a million Euros, or $700-750K USD (average over the last few years).
In another interview with James Meena, the head of Opera Carolina and a man of many hats, Meena discussed music rights:
Well, to buy just a score for the piano of an opera in the public domain it's $35, but if you buy the score for all of the instruments in the orchestra, it's more like $800. It's not cheap but it's not ridiculously expensive. But when we talk about a piece like "Peter Grimes" that is not in the public domain you are dealing with royalties and rentals, it will cost $2,000, maybe $3,000; then you have to pay royalties on top of that. The operas of Strauss are also still under copyright. These orchestra scores you have to pay $3,000 just to rent, you cannot buy them. Opera materials for "Turandot" you also have to rent, because the Puccini Foundation still gets money from the performances of it. [p. 365 Kindle ed.]
(Since it's the Britten centennial, the royalties and rentals must be adding up.)
Opera Carolina had a budget of 2.8m, down from 3.8m -- most of the drop was in government contributions -- and the difference between $800 and $3000+royalties is significant. When PNB produced ballets by company dancers last season, Peter Boal said the budgets were $3,000-$5,000 in total; Andrew Bartee and Margaret Mullin used commissioned scores by young composers.