My own theory is Narcissistic Personality Disorder. No, seriously. Everything fits. She just doesn't seem self-destructive enough for BPD. Granted, armchair analysis, but I get the feeling she'd burn through friends and relatives a lot quicker if she had it. And her self-absorption is beyond the norm for BPD...they tend to be a lot more concerned with what others think of them, if only to keep them for emotional/financial/other forms of support. I think she honestly doesn't give a shit about other peoples' feelings.

...yay for amature psychoanalysis!