Alright, so I was the one who bought coulthard fan's trailer here:
http://www.lotustalk.com/forums/f95/fs-wells-cargo-enclosed-trailer-super-light-cheap-195785/
It is actually a 7 foot wide trailer, not 7.5 as listed, as I did measure it. The Elise fits in it with little room to spare. There is a couple of inches of clearance measuring from each side of the mirrors when going through the entrance and probably 4 inches on either side when in the trailer. It is fairly easy to get on and off as he had a winch installed, you just have to take it slow and careful. There is room in the front to store stuff.
I did find that I could drive it in instead and could manage to wriggle out the window with the door partially open doing my best Dukes of Hazzard impression but that's only because I am short and just flexible enough to do it. I would not recommend it.
My tow vehicle is a V8 Toyota Tundra and it pulls easily but I only get 9 maybe 10 mpg doing highway speeds up to 75 mph.