S.,
I don't know if this would fit your beliefs or philosophies, but there is a great private Christian school in Frisco called Legacy Christian Academy (www.legacyca.com). Check out their website and click on Overview. From there, click on Classical Education. It is a great method of teaching that really fits the various age groups, and it seems to be a highly structured, challenging environment for learning. Also click on Head of School to learn more about the school, and then click on Capehart Seminars under Links to learn even more.
I don't have any children at Legacy; we live too far south in Dallas for that to be feasible, and my husband isn't open to private schools right now (our first daughter will begin kindergarten next year). I would love to have the opportunity for our girls to go to a school like Legacy (and there are other schools that teach from the classical perspective closer to us, so maybe we will someday).
I don't know if that helps...I know private schools are expensive...another option, but again Christian, is a private school that teaches a couple of days a week to supplement homeschooling. There is at least one school in Dallas that does that; it has a Latin name that I can't recall right now and can't find through my Googling; if you're interested, contact a local homeschool group.
I wish you the best in making a good decision. I was a music teacher and then a counselor in public schools. While I think the public schools do a great job in some things, I would prefer my children to be in private school. Much of the resources the public schools have go to highly identified groups of children, whether the group involves those struggling or those highly achieving. The middle kids, who are bright, quick learners, are often left without much support. It's not easy wading through your options, but I encourage you to do lots of research and to also realize that the best answer today may change over time for you and/or your daughter. Always be flexible but never give up!