I hope you get some responses from Forum members. If not specically from NC, there are a lot of posters who have been through a PTA-to-PTO transition.
However, if you do need to talk to other NC groups (and if you are willing to do some research), here's another lead:
Go to Guidestar (www.guidestar.org
). In the advanced search put "PTO" in the key word field and select NC as the state. I got 39 PTOs as a result. You might look them over and see if you want to contact any. (Whether or not they went through a conversion is unknown.)
My school is currently looking at converting to a PTO. Are there any NC PTO schools out there (particularly Piedmont) that we could talk with about how the conversions went for them?