The one I found in my hotel room, the very last one. After five days of stay in Tokyo, I only found three materials for my "SPOT THE ERROR" entry. Lucky enough.
In this case, the article "AN" is not required. The correct version should read" "There is enough space for you big luggage under the bed".
The room in the hotel is not spacious and things might get worse if you have a lot of things, like big bags, with you. To solve the problem, the bed is designed in a way that the occupants can push and store (READ: hide) everything under the bed. Brilliant!