NGSS just released its recommendations for an accelerated science pathway in high school. I haven't read through it much yet but I think it should be of interest to everyone.
The Accelerated Pathways developers use some of the best practices in gifted education - differentiation, mentoring, curriculum compacting, pacing, and telescoping - to explain and illustrate ways to organize an accelerated program of study. The Accelerated Pathways document also suggests ways to remediate knowledge gaps for students from the regular instructional program who enter the accelerated pathway later than their accelerated peers.
Other strengths include identification of the math skills needed in the accelerated pathway as well as a comparison chart of the shared concepts between the NGSS and AP Science courses, often the only courses available to advanced students. It is not common for educators to recommend acceleration as an appropriate choice for advanced learners. However, the developers embrace acceleration for our most highly able science students and provide specific direction to schools and districts on how to develop and deliver course content that is appropriate for those students who are ready and eager for curriculum that far exceeds the traditional course offerings.
http://www.nextgenscience.org/ngss-accelerated-model-course-pathways