I was thinking, maybe there could be a food shoppe where you can put your pets in if you have to go on vacation or something. This way, your pets won't die if your away. You could pay with TU, for each pet and how many days. I'm not sure if there is already something like this, or another suggestion like this, so I'm sorry if there is.

The only place your pets age or get hungry is on your profile, so if you put all of them in your showroom (this is valid for the ranch too but that's a place for selling pets) they won't get hungry :)

What Wolfspi said, and what you suggested is essentially the same thing as the Food Pen as it is now. You still have to pay TU for the food, then stock up a certain amount for however long you are going to be away for. c: So in a sense you've already gotten your wish!