OK, the full idea is that every pet, with two possible exceptions, can be ridden as a mount at the highest levels. The
two exceptions being the pet rock, as it would have to be a pet boulder, and the pet Plant idea, since it just wouldn’t make sense.
  As it is, the three normal pets have already been modified by Petrarch, so I doubt he’d be willing to make the changes I had in
 mind, but I figure you’ve got more clout on this than I, so I’ll give you the idea in its entirety.

Dogs would progress to Dire Wolves at level 10, and could at that point be ridden. Cats would progress to something like a Tiger
 or a Lion, at level 10, and could then be ridden. Birds would progress to Giant Owls at level 10 and could at that point be
 ridden. Every pet would have specials. Dogs, Cats, and Birds would all receive claw, and of the three, Dogs would be strongest
 at it. Cats would receive stealth. Birds would receive something to the effect of Invisibility sight, similar to the witch’s eyes, but
 this would allow them to see cloaked creatures, invis’d creatures, and secret doors.

Now, on to the exotic pets. First, Moogles are not a consideration in this, since that’s just completely different. Second, Ash and
 I have not yet been able to complete the progressions for all the exotic pets. Rest assured, when we get our hands on that
 Grolier’s CD, we will. Here is a list of every type of pet we had conceived of:

Spider, Snake, Horse, Lizard, Pig, Flying Insect (of a gigantic nature), Mouse, Frog, Plant (of a magical nature), Bear, Monkey,
 Rock Now then, we may not have finished all the progressions, but we do have ideas for almost all of these.

Spiders would start small, with little powers, but would progress to some type of Tarantula, and eventually turn in to a Giant
 Spider. Their specials would be a poisonous bite, which would become increasingly venomous with the spider’s level, and
 webbing, which would freeze opponents for a number of rounds. We toyed with the idea of spider climb, but figured it was
 probably too much and would not have much use anyway. Spiders would also have good armor ratings, especially at higher
 levels. Spiders would be very weak at low levels though, with few hit points. (Get it? ::crunch:: )

Snakes would also have the poisonous bite special, only with greater efficiency. The thought occurs of giving them a constriction
 special which also holds opponents. Snakes would progress to a giant snake of about 30 feet in length and perhaps 2 feet in
 diameter, so as to make them rideable.

Horses made the small number of animals that we thought we had completed the progressions for, unfortunately, Petrarch
 informed us that we would need 10 different progressions, and we came up with only 6. Nonetheless, it would be easy to add on
 4, i.e. Small Horse->Large Horse. Horses would be favored among fighters, as they could be ridden from level 2 on, level 1
 being a pony. The progression of horses would be as follows:

Yearling-Pony-White Lipzzaner-Shire-Heavy Warhorse-Unicorn-Pegasus

Horses’ specials are somewhat different. The level of the Horse would affect the damage of a charge by increasing factors. i.e.
 Heavy Warhorse = 3*charging damage. Also, upon reaching the unicorn phase, fighters could double charge on their horse. The
 horse might also Rush at this point. A Pegasus would lose the horn, but gain the ability to fly. The idea occured that a form of
 horn equipment could be found for a pegasus, but it would be an item which was found someplace hard, like Tijir’s island. This
 would enable the pegasus to double charge again. It should be added we feel this horn should only be found in an area you must
 fly to, so as to prevent double charging ponies.

Lizards also made the progression list. In place of claw, we thought perhaps bite for a special. We also considered camoflague,
 and leave this up to those in charge. The progression is as follows:

Gecko-Lizard-Iguana-Kimono Dragon-Gila Monster-Crocodile

As Crocodiles can get to be 28 feet long and are large in the first place, they would be rideable at this point.

Pigs were mostly just a thought. Eventually, a pig would become a Giant Boar. We thought perhaps giving pigs rush or charge,
 but not to the effect of horses. Pigs would rush and charge independently of their owners, horses would only do so on command
 from their owners. I think someone mentioned wanting a pig so they could find truffles. We have no comment on this. 
 Flying Insects also were mostly an idea. Try to imagine starting with something about four inches long with a stinger. Then
 progress it to a bigger insect, like something out of pre-historic times, when the dinosaurs lived. End it with something out of a
 cartoon. A big ass insect the size of a horse with huge wings and a stinger. Then put a saddle on it. Poison Stinger and Flight
 specials. 

The Mouse also did not receive much attention, and still doesn’t. It wouldn’t be too hard to make. Start with a large rat the size of
 a small dog. End with something huge. Hey, it IS fantasy after all. Just make it realistic fantasy; no pet Mickey Mice,
 capiche?Bite special.

Frogs go with Mice in development. Start with a Frog, end with…a big frog. We thought of giving it a poison special like the
 frogs of the amazon, but figured a good entanglement special made more sense. If you’ve got a 6 foot tall frog, I guarantee you,
 his tounge can hold humanoids and larger.

Pet plants? Why not. We’re drawing a blank on this one, but figure maybe plants would have spells or entanglement specials.
 ::shrug::

Pet Bears were the last to make the development list. Bears would receive very powerful claw specials. Other than that? Well, I
 suppose you could teach it circus tricks… Bear progression is as follows: 

Cub-Koala-Panda-Brown Bear-Grizzly Bear-Polar Bear

Polar Bears are the largest and most powerful of bears, and in our opinion definitely be the last stage of progression. Bears could
 probably be ridden at the Brown Bear stage.

Last is monkeys. Monkeys almost made the progression list, but our school’s encyclopedias suck, so we gave up. Nonetheless,
 monkeys would start small, they would be able to steal, and at the largest phases, would turn in to Apes. At level 10, you’ve got
 a fictionally large ape, probably about 7 feet tall. The progression of stealing for these Apes would end when they got so large
 they were very noticeable (king kong could jump you, but probably not pickpocket you as well as he used to). The special for
 Apes would be Pummel. If Apes don’t get pummel, they should get bite, but Pummel makes more sense.
 
Oh, almost forgot rocks. Ok, start with a lump of coal that spins around your head. With each level, it turns in to some thing more
 valuable. Always a jewel of some sort. With each level it would also gain 1 spell, and the skill for that spell if it did not already
 posses the skill. These would not be powerful spells. You would not have a pet rock with mana storm. Try a lump of coal with
 missile, then a ruby with burn, then an emerald with charm, etc. Eventually you would end up with a diamond. The idea of having
 varied progression for pet rocks also occured. So possibly two paths of progression, with the different paths getting different
 spells most of the time. This would be easy as far as names, since there are a billion rocks. As for coding? Well, I can guess it
 would be a pain in the ass. Perhaps you would have to bring pet rocks back to the Pet Lovers guild, send it to one of two rooms
 to advance…