clumsygirl and colby1911 -
As a previous posters mentioned, there is
Cary Ballet Conservatory which has a very formal, pre-professional program. The overall atmosphere may be more formal than you're looking for, but the classes are still "fun" and laid back while the kids are young. They do have "Broadway Babies" classes for ages 3.5 - 6. From their website: "Children experience an inspiring introduction to tap, jazz, and musical theater through animated song and dance activities in our carefully designed curriculum."
Students under 6 get to participate in a very informal in-house "Little Recital" - no expensive costumes! After 6, they get to perform in the annual end of year performance.
I attended a school similar to this (not in the Triangle). For the little kids, it's just the atmosphere you're looking for. Great teachers, no pressure, lots of fun. But as they get older, there's more of an emphasis on the formal program (which is great IF that's what they want). If your kids stick with it and decide they want to become serious about it, this would be a great place to do it.
Depending on where in Cary you are, a great option would be
Ballet School of Chapel Hill I'm in NW Cary, and it's about 20 minutes away. If you're in south or east Cary, this might be more of a trek than you're willing to make. They have a recital, but it's not one of those schools where that's the only thing they work on all year (and I know exactly what you mean by those schools!). They have great teachers, and they do have an option for a more formal ballet program with the older students, but it's not as formal as Cary Ballet Conservatory. They also have an AMAZING tap teacher there.
Triangle Academy of Dance -
Triangle Academy of Dance - could be one other to look at. I don't know much about it, I just looked at the website briefly when I moved here and started looking at schools.
Wherever you go, I'd recommend asking to observe part of a class, even if it's just from a window for a few minutes. See how the teachers interact with the kids, and if the kids are happy when they get out of class. I don't know of any with voice/music - but that doesn't mean they aren't out there.
Let me know if you have any other questions - if these aren't quite what you're looking for, I can ask around to see what other schools people recommend.