Take a look at the Susie Bug Tent. It is for just that sort of use.
It is 6' tall, 120" circumference, and 14.5 oz. That should give you a starting point. Perhaps you would be satisfied with a smaller one -- you should be able to estimate what it would take to make one that is 1/3 the weight.
They do custom sewing, and are well-recommended, so if you decide what you need, but do not want to sew it yourself, they may be wiling to do so for you. Giving them a call and talking with them may help understand feasibility.