There are no loopholes, the real loophole would be to buy a vendor item that is sellable for the same price you bought it. That simply doesn't exist. The idea of buying Portable Holes and later on putting on AH will still require time to retrieve your gold, and possibly you will need to lower those prices, cuz there are lots and lots of players who will use that tactic. Same with all other maths/resellable items. Weakest now, will be weakest after, again for 100th time i need to repeat that it will not change the BUY POWER which is not the goal, the goal is to remove ridiculous prices and it will be accomplished with "rich" people buying maths and competing between each other with the prices, meaning under-cutting each other. That is in my point of view a success.
IT IS REALLY, REALLY, REALLY EASY TO PILE UP THE GOLDS. The problem is not everyone wants to take a profession and do a little farming. It is much easier to come to forums to complain, that is the real problem. The only thing you need to start hoarding first is bags to fill them up with herbs/ores/green/white/gray items that are sellable for gold. Farm mobs that drop items that are sold for gold / farm old dungeons instances / gathering profs / crafting profs / dailies / normal lvl 80/85/90 quests that will give you lots of golds. That is how i did it, that is how anyone else can do it. Not everyone is willing tho.