According to recent post by Blizzard mod Tigole, certain ultra-rare pets are becoming bound to an entire account rather than soulbound! Here's an excerpt of Tigole's post:
The following items will be changed to "Account Bound " items:
• Murky (Blue Murloc Egg)
• Tyrael's Hilt
• Murloc Costume
• All of the collector's edition pets
Also, for the "pet" items, we're making it so that adding the pet to your collection will not remove the item from your inventory. With that change, you'll be able to learn Murky on any character on the same realm with the character that currently has Murky. It also means that if you own the original Collector's Edition, you'll be able to have all 3 pets (Zerg, Diablo, Panda) by mailing the items between characters. If this works out well in the Beta and people like the change, we'll keep it in.
So assuming this change comes to pass, it looks like those who enjoy collecting pets on a single character will be able to obtain all three of the original CE pets! This is just one more change in a long line of recent improvements for pet collectors. I'm sure I speak for everyone when I say, "Thanks, Blizzard!"