Chad Orvella is starting off the season at AAA. Jason Hammel isn't an ace, but he has great command and makeup and should be able to make it as a middle of the rotation pitcher. 1B/3B Wes Bankston can flat out rake.
Delmon, BJ, obviously, as you mentioned.
Guys that may make it to Durham this year (you have to remember that AAA is usually a brief stop for top prospects):
RHP Jeff Niemann
CF/RF Elijah Dukes should get a taste of AAA this year. Volatile player with crazy tools and projectability.