Sorry you misunderstood my suggestion. Actually a "floating gold standard" exists to some extent because the abilty to buy , hold and sell gold is again allowed in the USA. And there are multiple electronic gold exchanges for electronic digital gold, like e-Gold.
My suggestion was simply to point out that there *IS* enough gold to go back on the gold standard, it's just a matter of picking the fix. I would not advocate allowing it to float, once it was set. That as you point out doesn't accomplish the goal.
What you would propose is that once the amount of gold behind each dollar is fixed, it must forever remain so. So in the future as our economy expands, we would have to either acquire more hard gold from other sources, or not grow the money supply, which is a sure-fire recipe for disaster.
Since the rest of the world would not be on the same gold standard, if the price of gold went up, foreign governments and individuals could present paper dollars to our treasury for redemption in gold. We would either have to take even more dollars out of circulation, or else find more gold from somewhere else. (If you couldn't redeem paper notes for gold upon demand, then the whole concept of a "gold standard" becomes a sham.)
There is not a single major currency in the world that isn't a fiat currency. Returning to a gold standard for the United States is a sure fire recipe to destroy not only our own economy, but send the entire world into another depression that would make 1929 look like a good year.