Portable Garage

[BackintheFold]

Having bought a "waterproof" car cover from ebay (leaked through the seams first time it rained!), i'm trying to find a better alternative to an actual waterproof cover.

I have no real space outside to put up a car port, and what I seem to be heading towards is one of those folding tent type garages.
However, I've measured out the space they take up and the ones that are big enough to fit a QT in are too big for the space I have.

I am wondering if it would be possible to build a car cover, 16 feet long, 6 feet high with four support posts that I could build around the car. I could bolt the support feet to the concrete, and use some kind of plastic sheeting above to protect the car from the rain/snow. Perhaps that thick rectangular tube type plastic (IYKWIM) would be strong and could stand being unbuilt every month or so. Part of my plan is to use the car a month, then "garage" it, and repeat...

Ideally, i could wrap the sides with plastic.

Its all a bit of a pipe dream at the moment, but I want to keep the car at my house and protect it as much as i can.
Any brilliant thoughts welcomed!