I thought about this pet also when you mentioned the mammoth vendors last night, however the expense being worth it is questionable to me.

If you have the gold and don't need it for anything else, it may be worth trying to get one if your Auction House has it up. However if you buy the loot card you are looking at $180+ on ebay right now to get it. I know boxing isn't a cheap hobby in the long run, but I wouldn't spend that kind of money for something that Blizzard could break later on also.