You can sometimes see on the "Pet Auction" forum section that some pets are sold for diamonds, or a combination of diamonds and gold. Would it be possible to have the "Manage Pet" not only have gold for a sale type, but diamonds? Less scrupulous people might look at the sales and wait around in the exchange to snap up the diamonds.

This could also apply to other items tradeable items of high value or high rarity.

That would be nice, but then most players would put them for diamonds. Non-diamond players wouldn't be able to buy as many animals as before. Also, the rarer sylesti's would almost always be for diamonds.

Yes, but the owners of Sylestia can put up a system so it can't be too badly, or at all, exploited, such as a hard-coded limit for rares, Fableds, and the more common breeds.

This might also generate some more revenue for them as people will see the pet that they really want for diamonds and then will most likely go to buy some diamonds, or use some of the diamonds that they have stored up.

Another good idea would be to be able to send diamonds to other players like one can items or as a COD for an item.