The absolute lightest tent was made about 25 years ago in France at about 35 pounds for a full sized two person roof tent. It was called an "Oasis" and the design is brilliant,, like a zero gravity chair for two built into a tent. They were able to dispense with the mattress by using a mesh like on a catamaran and doesn't require a sport rack system as it has an alloy tube frame. I pair this with a lightweight AutoHome ladder that mounts under the tent when traveling. Not for everyone but I like it because I can quickly undo it from its mounts and place on the ground. The feet system keeps it up about a foot above the ground. It is a great design for what it is,- minimal.
