It's a shame you rule out a tarp. A silnylon tarp, with an inner bug net tent can easily weigh less than 3 lbs. It provides excellent ventillation. Setup is straightforward. you can use telecoping trekking poles that get down pretty close to your 15 in. limit, or, if riding in wooded areas, you can use dead branches or just tie to two conveniently spaced trees and carry no poles with you. If you make your own froma kit, you can choose from a range of colors. and finally, you can get a kit with everything you need to sew your own for less than $100.

In short, the tarp can meet all your requirements except for not being a tarp.

Another advantage of the silnylon tarp is it packs down to an embarrassingly small volume.