In patch 4.1, this will stand no longer. The Wowhead blog is reporting the Wintersaber grind is being turned into a series of daily quests that put you in charge of the care and feeding of a Winterspring Cub on the PTR. After 20 days worth of dailies which earn you Winterspring Cub Whiskers, you'll be able to turn in the They Grow Up So Fast quest for your very own set of reins. In addition, you can buy a Winterspring Cub permapet from a vendor in Everlook. It's Bind on Equip and sold by a neutral vendor, so even Horde and Bloodsail Admirals can get thier hands on it.
Savvy players will probably recognize this revamp as bringing the Winterspring Trainer grind in line with the Venomhide Ravasaur grind for the Horde. It's easier and less tedious, but it takes a regular time investment. Luckily, said investment shouldn't be too hard, since you can teleport to Hyjal from Stormwind and fly to Winterspring relatively easily.
With this change, we can probably expect the Winterspring Trainer faction to go the way of the Shen'dralar and the Zandalar Trolls. If you want to grind it, you'd better get on it now. But if not, you can have fun with a new set of relaxing and rather cute dailies on your way to another mount come patch 4.1.