Hey this is interesting:
That cleat-and-looped-steel-cable hardware setup you guys updated to looks tidy (and sturdy!) -- but it's actually a different setup from what I was expecting to see.
On my buddy's 1998 Chevy SMB (Austin-built), I believe the penthouse bed is suspended from the roof by a set of
adjustable-length straps.....(which do fasten themselves to the bed with cleats like you're using.)
Their adjustable operation is pretty neat ---- if I recall correctly, you can easily determine if you want to snug the bed right up close to the roof (for maximum headroom), or you can let the straps out a bit, effectively lowering the bed a number of inches, if you want more space up there between the bed and the roof (for instance if you want to store all your bedding (and maybe some other clothing or clutter) up there during the day while you're camped somewhere.)
Will have to see if he might post some pics of his setup to confirm this.
EDIT: Hey, btw you guys -- if it wasn't obvious --- despite mentioning the setup I've observed and admired on my buddy's '98 SMB -- I mean no slight against the looped-cable-and-cleat setup you guys chose to craft! I'm quite envious of your setup too. The original 1995-vintage bed-hanging strap-and-hook hardware on my rig is indeed marginal at best.....you're both creating some overdue inspiration/motivation to pursue an update/improvement.
EDIT 2: *by the way, sorry if this ramble about slightly-different straps/hardware is in any way taking the OP's intended direction for this thread off-course. Really keen to see the same pictures of the rear roof-to-penthouse-bed-strap attachment hardware that the OP BrianW is looking to see.