"You have a short bed."
Translation:У тебя короткая кровать.
My Russian teacher told me once that when using adjectives, Russians tend to drop есть. But I do not think it is a very hard and fast rule. Even without adjectives, dropping есть does not render the sentence incomprehensible. From what I can gather, есть is there just to put emphasis 'there is' something, drawing contrast to the use of нет which of course implies that 'there is not' something.
I agree. Much of these lessons are just "gotchas" to take away hearts from beginning learners. The first I've ever seen where a heart is used to slap people.
I, too, learned that есть is omitted when talking about personal qualities. But no other omissions were mentioned.
The rule is У (genitive) есть (nominative) - that which is possessed is Nominative Also У (gen) (nom). I think the есть need not be used in this case. It is not a question, its a statement, and the existence of the bed is clear. "Do you have a short bed?" with a ? is different.