Indeed. Credit is money; ultimately anyone can expand the money supply with an IOU.
My thought on this would be a dynamicaly stable currency. estimate debt and transaction activity, and the more debt and more liquid activity there is, the more deflationary currency should be. the less debt there is, and the less of a percentage of the money is actually in-use, the more inflationary the currency should be. this, though, is fairly off-the-cuff.