One thing that might prove to be quite useful for when we enter Cataclysm:
Camp Auction House whenever you have time, and try to find good deals on:
Azure Whelpling - Item - World of Warcraft Azure Whelpling.
Dark Whelpling - Item - World of Warcraft Dark Whelpling.
Tiny Crimson Whelpling - Item - World of Warcraft Tiny Crimson Whelpling.
Tiny Emerald Whelpling - Item - World of Warcraft Tiny Emerald Whelpling.
Try to get as good deal on them as you can on your server, and save them safely. Now, weather they will still drop in cataclysm or not, i can not say. But even if they do i'm certain they will only be harder to obtain, with a possibility that they won't drop at all.
So a month or so after Cata has heated up and people got their 85, these items should be worth quite allot more than what you bought them for.
Also if you check through some sold items vanity or useful ones you can see if any other match this kind of trick.
These 4 items should provide a decent profit especially if you obtain more than one per.
And you can probably find more items to take through this scheme.
Hope this helps someone, and also feel free to comment here if you found any more items of this sort, and share it with rest of us.