You can find same height tubs probably not for all 3 size tubs though

Sterilite 6 quarts and 12 quarts have the same height

Sterilite 7 quarts and 15 quart have the same heights

Sterilite 15 quarts and 32 quarts have the same heights

Best would be to check sterilite and rubbermaid sites to give you an idea, also check this site it will give you an idea on Iris tub's sizes http://www.reptiletubs.com/