Meanwhile, bitstamp volume continues to exceed Mt. Gox volume of actual trades by at least 50% each day.
Not true.
Bitstamp publish their total volume only. MtGox don't publish a total volume, but splits it into individual currencies. If I deposit EUR on Bitstamp and withdraw EUR from Bitstamp, it is still counted as USD volume. On MtGox it would be counted as EUR volume. To compare the two you need to add all currencies on MtGox. Many people don't know this.