You might want to check out these two books: Academic Advocacy for Gifted Children by Barbara Jackson Gilman, and Reforming Gifted Education by Karen Rogers. Malone Family Foundation website has summary of Karen Rogers' book:
http://www.malonefamilyfoundation.org/educating_plan.html.I second others about Davidson website. They have links to many studies that have been done about efficacy of different programs for the gifted. Here's one that hopefully help answer some of your questions:
A Best-evidence Synthesis of Research on Accelerative Options for Gifted Students by Karen Rogers
http://www.davidsongifted.org/db/Articles_id_10004.aspx-Paula
