It seems like maybe someone can, because as I started typing this, Gox and Stamp USD last prices were $0.05 apart and have been coming within $1 of each other the last 1.5 hours at least.
I think you are mistaken. Bitstamp 's price is being incorrectly reported on a few ticker sites, but if you go to their page you will see there is still a large gap with mtgox.