I have seen two of the smaller, single axle trailers from the late 1960s/early 1970s with the "Hammock Bunks" over the dinette or front lounge. While I didn't actually measure the bunks, they appear to be a bit wider than those that were mounted over the center twins in my Overlander. I don't know just when the "Hammock Bunks" were discontinued, but suspect that it was prior to 1980 as I don't remember seeing them in trailers much more recent than 1975/76.
Kevin D. Allen
WBCCI (Lifetime Member)/VAC/Free Wheelers #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 VORTEC/4.11 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 Liter V8/2.70 Final Drive)