I put together two of them. I bought the drop down frames for 1300.00. Both 6.5 x 12 x 3 ft V. Then took a double flipover house and took it off the sled and made a bracket of both sides of the trailer to hold the frame work. Its the same principal as the Blackhole only I had roughly 2000.00 in it . I put 5 catch covers and one spearing catch cover and could drive over the covers with my 6x6.
The other one I used a 6 x 12 pop up and had tie downs in the corners to hold pop down. Plus you have a nice utility trail to haul your ATV or lawnmower.