Orrin Hatch takes my advice. Well, not quite, but here is what he is proposing for the Federal Marriage Amendment(from National Review):
Civil marriage shall be defined in each state by the legislature or the citizens thereof. Nothing in this Constitution shall be construed to require that marriage or its benefits be extended to any union other than that of a man and a woman.
It's very close to what I suggested, although I would go slightly farther, and add after Constitution "nor any state constitution, nor federal nor state law." This, of course, requires an additional phrase at the end which says "unless explicitly stated otherwise." Hey folks, it might happen.
Update: For once, my Old Post, New Post scheme made my post less clear. For that reason, I repeated the Title at the beginning of the post.
New post: More here.