As I am sure you know the way attachment problems manifest in a child are as unique as the families wrestling with the issues.
From a clinical perspective this is a good starting place: Handbook of Attachment: Theory, Research, and Clinical Applications. or Becoming Attached: First Relationships and How They Shape Our Capacity to Love they are a bit dry, but full of knowledge non-the-less.
From an, “Oh shit, how do I do this???”, place I would start with one of these comprehensively helpful books: Help for the Hopeless Child: A Guide for Families or Healing Parents: Helping Wounded Children Learn to Trust & Love. This site is also helpful: http://www.attachmentdisorder.net
In addition to gathering information I think the single most important thing to do is remember to not navigate caring for such a child alone, as a caretaker or parent. Talk, talk, talk. A very lonely and sacred task has been taken on and self-care is just as crucial in this instance as is the care for the child.
For the immediate family, finding professional help that is familiar with modalities involving attachment therapy and play therapy would be something I would call essential. Suggest starting the search here: http://www.theraplay.org/8454.html. While any professional intervention would be helpful a therapist gifted in the art of play and children is the most helpful. I believe this is something that can be eventually weaned off, but it is a time saving/life saving need.
My children have faced neglect and trauma that many an adult could not bare. At each developmental stage my children seem to relive their trauma and require from us various interventions that help them know they have a harbor of safety in us. It is also key in learning to give our whole selves to one another. As any of us know this is a priceless gift. Since a child’s language is play it is crucial to integrate play into the parent-child interaction that encourages trust. There are many examples that I could give but I fear this post is getting too long. PM if you have any interest. I will point you to another book entitled Playful Parenting. It offers concrete examples of how to turn power struggles into play and every day moments into attachment. One doesn’t need to be a parent to see the benefits of what the author suggests.
If you find yourself in an immediate situation with a seven year old child who is wanting to harm self or others, somehow turn the situation into a game.
For example, if she is using an object to cause harm say, in a very excited, exaggerated, and earnest voice, “Oh,insert name, look at me! (wait for eye contact) You didn’t hear???? That has to be hidden away from the fairies!” Then produce a brightly covered cloth and wrap it around the object (even if it is in her hands). Then elicit her help: “Hurry, help me find a safe place!” then quickly move, with her, to a place where the object and cloth can be hidden.
Somehow use redirection to turn the situation into a game and tell the parents to get some help!
Finally, I hope for this child and her family healing. Often, when my son strikes out and cause harm to himself and others, it is the only way he knows to ask “Are you stronger than me? Can you keep me safe???” I hope the adults in your precious child’s life can help show her just that.
edit: @skfinkel, I heard that broadcast, it was on “This American Life” here is a link and synopsis for the curious: http://ukraine.adoptionblogs.com/weblogs/this-american-life-unconditional-love it is quite moving!