Size wise they do pretty much follow a standard. From what I understand this is because glass is supplied in standard dimensions and is cut leaving the least amount of scrap. If you look at the tank sizes, one supplier will call a tank a 40 breeder, another calls the same tank a 40 long. Then they both sell a 40 long, but different dimensions.
That Casco site is a pretty interesting site, lots of high end products. I’m wondering if the show tank size is common to just acrylics, as I’ve never seen it in the more common glass tanks.