I think you did a wonderful job capturing these lovely images. My favorite is the last one..I love it!!
I agree with the comments Charles made. The D700 is a wonderful tool...go ahead and push it. Up your ISO...watch your histogram. As long as you aren't underexposing noise won't be a problem and you'll be able to up your shutter speed to get crisper captures.
Question: How did you get the opportunity to shoot ballet? This is one thing I would love to have the opportunity shoot.
Thanks for sharing...Yvonne