Back in September, a couple of friends and I went to Crater Lake, Or and camped. We grossly underestimated how low the temperatures would be, and spent a sleepless night trying to stay warm in our giant tent. I really wish I had known about the lippi slek bags before that trip being able to warm your self by the fire and then walk into your tent without getting out of your sleeping bag would have been heavenly.
This is a UK company that sells these, if I find a US supplier I will post the link here.
The cost (with shipping to the U.S.) is 103.95 Euros which by todays conversion = $153.91 US Dollars.