Do yourself a favor—don't get any of the Taiwan Giant boxes (that goes for Trek, too). They may be slightly more dimensionally favorable, but they are much more fragile than the boxes coming from the mainland China factory. The Taiwan boxes are a bit more yellow than your average cardboard box.

IMO, with the price of those boxes posted earlier, there is little reason not to buy a Serfas case, or the like--they can often be bought used for around that price.