Little confused about those sizes. Molded manufacturers designate their models by total length. A Scamp
13, for example, has a 10’ cabin. Tongue and bumper typically add 3-4 feet. Sounds like you’re looking for 13-17’ models.
They’re not being weird or deceptive, BTW. Airstream does the same. It’s the original convention for travel trailers. I’m speculating the large-volume makers of conventional framed trailers switched to cabin length as a marketing ploy to disguise on paper how big their products really are!
Welcome to the world of lightweight, sensibly sized molded fiberglass trailers! Best wishes finding something that will work for your needs. Important question is whether a bathroom is required. Bath with bed and separate sitting area generally rules out the smallest units. Your budget, however, points toward a smaller unit. You might find an older 16’er that has a bath. If you don’t need the bath, you can find any number of 13-15’ models with a bed, galley, and separate seating area.
I assume what you have is a Jeep Liberty
... with a tow rating of...?