Rmmcart, I'm sorry that your daughter is still out of touch. I can imagine how much it must hurt.
I'd like to offer my perspective as a daughter who's been estranged from my parents for many years. I'll preface it by saying: take what you find useful, discard what you don't, and keep in mind that it is my experience and might be only partially (or not at all) applicable to yours.
Growing up, my parents invested far too much of their emotional well being in me. What I mean by that is, if I was in a bad mood my parents were crushed. If I was in a good mood, they were elated. From a very young age I felt burdened by their emotional ties to me, as if I couldn't have any negative feelings lest it hurt them. So many times when I was going through a rough patch and tried to talk to them about it, I would end up comforting them. What they thought of as closeness was more akin to codependency. I always felt like I was the parent in the relationship -- they were truly helpless, and from a very early age I had to take the lead in situations -- little ones like changing a tire at the side of the road with my father when I was twelve because he couldn't figure out how to do it, to explaining to the ambulance attendants the details of how I hurt myself when I was four (and lying on the front lawn bleeding from a leg wound that nearly required amputation), because my mother was in hysterics and couldn't speak.
My rift with my parents was caused by a lifetime of hurts, some small, some large, and then an astonishing betrayal and breach of my trust. I have worked very hard with a therapist over many years to better understand and get past my issues, to learn how I contributed to the unhealthy dynamic of my relationship with my parents, and to grow and change. For whatever reason, they have not done any introspection to figure out where and how they might have contributed to the rift, instead assuming that I'm being stubborn and that knowing they still love me is enough to bring me around.
My parents have been making concerted efforts over the last several months to re-establish contact with me. Although I'm polite to them and take their calls, I find their contact to be intrusive and unwelcome. I don't hate them, don't really have any ill will toward them, but I am no longer comfortable having them as regular fixtures in my life especially given that they want things "the way they used to be" rather than being willing to build a new relationship.
I agree with the others who've suggested that you work on personal growth. It might even be worth speaking with a therapist, just to explore your side of the situation and figure out how to make yourself better, stronger, faster (sorry...slipped into The Bionic Man for a moment...). Your daughter will come around, or not.
I also suggest that for now you back way off from any further attempts at contact with your daughter. She knows you love her and want to rebuild a relationship with her, but her current state may be such that your continued attempts at contact are off-putting rather than welcoming. The ball is in her court. Leave it to her to pick it up when she's ready.
Trinity