By the way, it is not above God's power to bring out pet back to us when we go to Heaven someday. After all he created the pet specially for us in the first place, he is more than capable to do it again. Heaven will not lack one thing that will keep us happy, if it pleases God as well.
There is a book on the subject called “Cold noses at the Pearly Gates”.
The pets in Heaven books don't exactly provide the guidance needed to comfort these folks.