I can't help but think these prices represent people confusing a currency being useful with a unit of the currency being worth more. Obviously this is true at the extreme case that a useless currency is worthless in any quantity. But it doesn't really follow that more trading of goods and services in Bitcoin would cause the price to increase. This wouldn't need to happen until some substantial fraction of them are in the hands of people spending them instead of holding them speculatively. Currently the amount of Bitcoins that need to exist to satisfy all the commerce is tiny.