Because I am stupid and poor, I have to do 10 times the work for 1/100th the reward. Wherever, possible I try and keep it as simple as possible.

Some simple calculations.

US Treasury Balance Sheet.
http://www.ustreas.gov/tic/debta906.html
$10.3 trillion in external debt of the United States according to the balance sheet of the US Treasury as at September 30th, 2006.

US International Reserve is $53.5 billion plus their gold. $175 billion of gold at current prices.
http://www.ustreas.gov/press/releases/20072131355284516.htm

So, forget about derivatives, leasing, and gold repurchases for a moment. Take the US treasury at their face value.

For ease of simplification, external debt is 50 times the $200 billion in gold the US has. (Internal debt of the United States is presumably able to be taken care of easier than external debt).

If gold were to balance off the external debt of the United States on a 1:1 basis, gold would rise 50 fold, assuming they could get the gold back from those that have leased it and all derivatives associated with the transaction could be honored. This assumes that the value of the debt does not fall.

This becomes important because the December TIC data showed foreign selling.

Federal Reserve Balance Sheet
Alternatively, one can look at the Federal Reserve Balance sheets to get an idea of what type of move gold would have to make to balance off their balance sheet.

If gold were to balance off the currency in circulation on a 1:1 basis it would have to rise about 4.5 times from the current price. $804 billion in circulation divided by $175 billion in gold. Again this assumes that they could retrieve the leased gold and honor the derivatives associated with the transaction.
http://www.federalreserve.gov/Releases/h41/Current/

A statistic of note for FED Watchers.

Currency in Circulation on the Federal Reserve Balance sheet as at December 31st, 1996
$446 billion. http://www.federalreserve.gov/Releases/h41/19961226/

Currency in Circulation on the Federal Reserve Balance sheet as at December 31st, 2006
$816 billion. http://www.federalreserve.gov/Releases/h41/20061228/

This is a compound growth rate of 7% for the past 10 years. Assuming a constant compound growth rate of 7% means the Currency in Circulation will jump to $1.6 trillion by 2016. To balance the Federal Reserve balance sheet by that time would imply a nine fold increase in the price of gold. (By the way it is hard to argue that the inflation rate is less than the rate of growth in the assets of the Federal Reserve balance sheet, or the growth in the currency in circulation).

Buy all the gold your balance sheet can balance!