My own feelings about toddler sized beds is that personally I wouldn't bother. Because they are short length-wise their time of usefulness is going to be quite limited and before you know it you'll be looking for somewhere to store it so that you can fit a full single in the room. If being close to the floor is important to you i would instead invest in a single futon. Then at least you be able to fold it up and store it easily and also offer it to adult guests. Also buying a single futon means that you will only have to buy the next size up linen... ie go straight to single bed linen.

But you do what's needed. Luckily my toddler didn't have an issue with going into a full sized single. We have a king single futon though which is very handy to have in the house and easy to store.