Kramer Haulmark sells a low hauler for bikes. They come in a 20" length. They are only 6' 3" tall. They will ride behind your truck with out that big brick feeling. You can put the whole trailer in your garage. It will carry 7,500 lbs. and you will have room for tools, tires, a few spare parts and the harley. They are not the cheapest and not the most expensive. What ever trailer you get make sure you get the next load wieght tire up from the stock ones it comes with. There should only be about a 50-70 dollar differents. Your gas mileage will go down between 1-1.5 mpg has compared to a 8' trailer which is about 2-3 mpg. Have you looked into a soft top trailer? I use an open trailer and cover the car with multi padding and covers. There was a low hauler on e-bay in red about 4 months ago. It went for about 5,800.00. New it was 8,200.00. I am saving for my trailer. After you buy the trailer, have it undercoated to get a longer life out of it.
Rick Ps you will pay big bucks for the aluminium trailer. They are nice but the 8' height still catches the wind.