My Ikea mattress came rolled up very small. Not quite suitcase-sized, but if you find a way to get close to such a size using simple tools (something you can fit in a backpack or carry-on), I can see this happening. One wouldn't need a human-size suitcase to pull that off.

Note that this is based on mental estimations of a ten year old memory. I may be off about how small it was, but I think the estimation should be accurate in essence.