There's been some discussion on this issue quite recently on some earlier threads. You may have already discovered these, but if not check them out to see if they offer any helpful thoughts:

http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/120730/1.html

http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/119689/2.html

I cannot offer any personal advice on this issue but from what I've read, skipping first grade seems to be more common since many schools are reluctant to allow early entrance (I imagine this is exacerbated by high levels of redshirting in some districts). I think language immersion programs might also be an excellent option, although I've read little about this on this forum. I was in a French immersion program all through elementary school, which was very successful for me. Good luck!