I do not know how small you could fold them but we use Merino Wool blankets which keep us warm in winter and cool in summer. Below us we sleep on a fleece blanket on a reflex foam mattress.
Apart from the unit itself, beds in tents or caravans are used for longer than any other piece of kit and therefore more money should be spent on these than anything else.
There is nothing that will put people off camping more than having a bad night's sleep.
I use one of those vac bags, but you roll it up to remove the air, saves having to think about what you will need to get the air out. However, its not very big, so probably not much use. I think I got it from pound stretchers.
I was at Marble Arch Primark at the end of the Summer holidays and got 2 x fleece blankets for £2.00 each. 1 for no. 1 son to take to uni this Saturday and 1 for me. There is no reason why, as previous posters have said that 2 or even 3 could not be sewn together.
I put mine inside my sleeping bag on cold nights to keep my tooties warm.
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