There are ponytail models out there where the tail part can be made invisible, and this would be a good partner provided the hair colour could be matched well enough. You could add a little tie to disguise the joint.

For myself, I'd prefer something a little less Rapunzel-ish. :-) By which I mean shorter... Although now I think on it, the long version has possibilities too.

What I'm trying to say is, I'd like this. :-D