This is rough and not completely thought through, but........
I'd like to try something like this (on the Darien UL). The overcover is sized exactly the same as the net. There is a strip of fabric approx 8-10" wide around all 4 sides with a shock cord channel to accommodate 1/16" shock cord. I'm not convinced yet that it would actually require the shock cord. Each of the 4 coners are overlapped forming a pocket. The end pockets fit over the hammock peaks, while the side pockets can hold a heavy item (shoe, water bottle, etc) to weigh the sides down. For windy/stormy weather, the side pockets would be fitted with a tie-out loop for cinching down a little more secure. The sides at the asym points could also be hooked to the UQ corners. This may actually help keep the UQ in the proper asym arrangement, but I don't know. The fabric strips along each side should open up enough to wrap around the edges of the hammock, sealing against cold drafts. There would be a Nanoseeum window at each end for ventilation, yet in a protected area so that a breeze can't easily get in.
The whole cover should be able to be built with 3yds of 60" wide fabric + a little nanoseeum & any hardware required.
The DangerBird overcover would need to be slightly different on the sides to accommodate the existing tie-outs on the hammock.
The name for this design?
I'm thinking the Lunchlady - "sloppy joe, slop, sloppy joe"
Disclaimer - I haven't tried this exact design yet, just ran tests on a couple similar overcovers. This design is just sitting around on my to-do list.