Jael and Sisera, from the Maciejowski Bible, ca 1240, Jael and Sisera, follower of Van Eyck, 1440-1450, Death of Du Guesclin 1455-60, and Death of Du Guesclin 1479-1480. The second Sisera isn't in a bed, but I included it both for the clear depiction of the tent peg and the gap between the bottom of the tent wall and the ground. You can click on these images to enlarge them.
Anna Nenarovoa has Pinterest board devoted to many, many images of Judith and Holofernes. The virtue of these images as that the artist is depicting the kind of beds that might be plausibly used inside a tent. These are also relevant to other tent furnishings, such as horizontal rods for curtains and other things to hang from.