http://www.luxeoutdoor.com/eng/index.asp Huge bat wing tarp has possibilities especially with a bug tent. Still comes in at 5lbs combined but offers a lot of set up options.
Lot's of creative ideas in their stuff. I see that the tarps are on ebay. $81 for the 16 footer and $69 for the 13 footer.
3lbs and 2.2lbs respectively.