Two Skyboxes

Hi, guys! I was wondering if there was a way to have two skyboxes. Well, not exactly. I would like to achieve an affect of having a bone skybox with just blue skies, and another, rotating skybox rendered in front of it with clouds on it. This would make a fairly realistic sky. Is this possible? If so, how? Would I use a sphere instead?

Thanks!- YA

Take a look here and there. Not exactly what you need, but maybe you can work it out from there.