I just learned a new nightmare that will also prevent me ever moving back to America.
In Victoria, a used mattress has to be clearly labeled as such by law at sale.
In many American states, mattress stores can simply reupholster a used mattress and sell it as brand new.
I may never sleep again.
Does the #EU let you import American mattresses? I'm pretty confident Americans can import European ones. Also, there are new artisinal Amish made mattresses to consider. 
That's a good question. Bed sheets aren't precision instruments, so they're close enough that you just want to be aware of the American size measurements in CM, which is easy to grab a reference for. In general, Americans prefer the American "queen size" which is in-between two common European sizes; that's where the misunderstanding comes from. You can mix the continents' gear if you pay attention to what you're buying. 
Lesley Carhart 
Pseudonymous 
acb