Cargo ship wip

I wanted to build a stocky ship, something in the manner of those endearing b-movies of the past where the ship crawls by the camera at an extremely slow pace yet the sound effects people add a jet engine fly-by sound.
     I wasn't intending anything too elaborate and I fancied coming up with a kind of cargo duty craft. The fun of this project is that I would like to have some slight plausibility to the design and so I figure the cargo bay would be detachable, and I was planning on adding a type of frame over the top but that would go into Eagle territory. I would like something slightly different and reckon I could turn that idea on its side so to speak, and have the frame go around the side of craft, which can wilfully add to the stocky aspect.