Normally when I go to Costco they have flashlights located in either the automotive aisle or the tool aisle. However a week ago when I went they had moved the flashlights to the seasonal area located in the center of the store (I believe Costco follows a general layout in all stores. However if not, flashlights are generally located in the aisles to one side of the store, while seasonal items are in the center of the store. At least in the stores I visit. ) Another factor is that the POS system Costco uses can only hold 2000 items. I say only because in the past I have found that they will shelve an item for the weekend in order to bring down another that they wish to sell over the weekend. After the weekend is over up goes the promotional item (for lack of a better term) and down comes the normal stock. I've no idea if this is still the case, though I have no reason to believe it is not.
And for what it's worth, they did have the 1 watt coast light, small lanterns and a couple of thor lights in stock when I was there a week ago.