I built a 3m tunnel greenhouse a while back and it worked out pretty well, but I did think that the shape looked a bit like one of those airstream trailers. If I was going to build one as a trailer I would go for a small one that was easily towed by an average car.

This is exactly the same geometry as the greenhouse but just has two tunnel sections joining both halts of a 2v dome. It comes out at around 2.2m (7ft) wide but the door is a bit low, 1.3m (5ft) tall. This is a first draught so could do with some refining, the van sits high on the wheels and could do with dropping lower I think

Left side showing off centre door


Top down view


Right side view

I''ve shown this one with matching colours from the car but I think it would also look cool if it was polished aluminium with smoked glass. I''ll check sizes and scale to see if it would be practical as a small trailer and maybe do some internal sketches.