Just a thought before you go out and buy something. If you have a friend in construction you may be able to get some Tyvek and make a cheap gear hammock to your own specs. It's recommended you put it in the dryer with a shoe to make it less crinkly sounding. Added bonus, the stuff is both strong and really really light. And if it got wrecked , hey, it's cheap. Extra bonus, you're likely saving it from the landfill so there's an added green factor.
I made my own Tyvek tarp a while back, and while I prefer my hexfly, I often bring it along as a backup as it's so light. And in a pinch if I go to ground it's an awesome groundsheet. And despite what you hear, it doesn't matter which side is up, it works great either way.