Solution: small, low expandable bed, which can be easily fitted to the backpack.
Prior Art: US Army expandable beds.
There is a saying that one should not patent things, which one does not intend to use for making profit. Hence, I post my imagined contraptions on this blog. They vary from trivial (better dog cage) to profound, to loopy (designs of starships). Some of them obviously work but are direct extensions of the known products (hence, the Prior Art), others might not work All comply at the first glance with the known laws of nature. Have fun!