Looking for a bag with screen over the opening ? A Bivy bag is a great choice, but not a cheap one http://www.mec.ca/Products/product_listi...D=1126142861390 .

Also there are a lot of new tents/shelters out there with modular components.

A separate mosquito net is a great thing to have handy. Lightweight and cheap to buy. http://www.mec.ca/Products/product_listi...D=1126143411670

Hope this gives you some ideas ...