J.B.
I'm signed up for Park Cities Day School at Mockingbird and Inwood starting in December. I can't tell you much about it except that I liked the way it looked....
http://www.parkcitiesdayschool.net/
I also looked at Park Cities Community School near SMU. I liked it, but it was a little expensive for what I was wanting (I only work part-time and needed something lower cost). http://www.community-school.org/
I have a crazy spreadsheet of the places I looked into if you want me to send it to you, just send me a PM.