Giro Atmos for road riding, can pull my pony tail through. I have fine hair but a ton of it so it is thick. I don't particularly care for the Giro but I paid $170 and it fits to protect my head so I will wear it until it wears out. 
I *think* my Rudy Project Kontact can do it but I only wear it for mountain biking and like to put my shoulder length hair in little pigtails. I have gotten my grabbed by trees and it scares me so I keep it down low on the trails. Their helmets are crazy comfortable but you may not see them in shops. This is my favorite helmet out of my 4 previous (including the Giro).
I have seen people wearing Trek helmets with hair in the back. Are you going to a shop? Just try them on.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan