5 stop push...gotta love these new sensors!! I regularly push 4 but that a 100 ISO is amazing. Try that with a 7d, 5dII or III or 1D4 or any other DSLR on the planet.
If you are shooting dress rehearsals the art director has to be more flexible if he wants the shots and wants the rest of the staff to see what they need to see in the production before live audiences see it.
If you have free range, that is a big help. I like the idea of the 80-200 but on a tighter budget, a 85 1.8 is a very effective lens on DX as a short tele with great optics and speed and only $450. Grand jeté when executed well are easy to pan because the better dancers appear to be suspended in air for a full second or more with mass-less bodies for those moments, their path is elegant predictable and slow at the apex. If it is beginner or student performances the impression of weightlessness will be replaced by an athletic leap that is still predictable but is not as smooth nor having as elegant line so a little higher shutter is needed to freeze. Mariinsky is my favorite but not the oldest here, I was thinking of the 256 year old Alexandrinsky Theater that has been carefully restored recently and beautiful. There are 54 classical venues within walking distance of my apartment so it is a great place for culture, if I am not spending all my time in dance clubs dancing until 6am several nights a week;>). Although Mariinsky is the premier ballet theater, Alexandrinsky Theater is a mere 22 meters from the most famous and prestigious ballet school, the Vaganova Academy. Alexandrinsky Theater stages primary drama now however. There are 330 drama theaters in the city. Another advantage of the D7000, it is so quiet that you can get permission to shoot from the audience if you talk with the production staff or theater admin. I proved my D7000, in quiet mode not be heard on stage so got a letter from Mariinsky Theater saying it was permitted. My D800 can't be used during performances due to noise. Q-mode D7000 is really quiet.
Lenses, yet, fill the screen and don't crop, that will be the biggest solution to noise. Shooting at the lowest ISO you can, even if it is way under exposed will give cleaner results if you shoot RAW and can boost the exposure in post. The D7000 is good for a full 3-4 stops of recovery.....that is why we love Nikon's. What else in DX could do that? I think I would approach this one with a bit of arrogance to match the art dirctor, like Perrone said, "you want action shots? OK, give me light, otherwise I am outta here", failing that, a 85 1.8 shot close enough to fill the frame and time the leaps, lifts and slower pas. Even an allegro arabesque develops slowly and very predictably with a line you know exactly where they are going to be moment to moment. Lifts in ballet are also slow in developing because the real skill and tremendous athleticism is focused on seeming smooth, light and ballon. Those might be done briskly but are easy to predict because of the the smoothness in which they develop. A Entrechat, on the other hand where there is in intentional appearance of speed and abruptness, even when you know it is coming needs higher shutter speeds to freeze movement, or just guess. If the art director wants these shots for evaluation of the forms, shoot from slight higher then center line so the relationship between the torso and turn-out of the hip to toe can be clearly seen, they will be interested in that. If your work is for publicity and public viewing, demand more cooperation, your images are going to help put butts in seats. All that aside, don't be afraid of under exposing so the featured dancers are still bathed in shadows, as long as some highlights are there to describe at least one edge, that is enough for compelling promotional shots that convey the romance and etherealness of the performance. Shadows are not the enemy in such scenes, better than starkly lit sets that do not look so good from stage, they look good with dim light 10 rows out in the audience. If for artistic evaluation for the director and choreographer, you need detail, and do not cut off feet. They need to see lines and form, turn-out and position and they do not have to be as pretty as detailed. Put some photos in your gallery then post a link to them. Stan St Petersburg Russia