All you need is a piano hinge that is well attached to the wall.
For the outer support, they're using internal cables that appear to attach to the same outer points as the canopy supports - or very near them. You could use external poles, internal or external cables, or a ridiculously strong frame and custom hinge with a stop.
Internal cables are easier, allow the bed to be tilted in by one person, without having to go outside and untangle a cable that goes astray, and can be used as the 'handles' to pull the bed in.
But cables will always wear on the canvases and leave marks. Do you want those marks inside? Or outside?
Either way, you'll need a canopy support inside, and those wear on the canvases, as well.
I'd just go with internal cables.
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You can buy canvases for slide-out or tip-out bunks from several places and skip the R&D on the canvas.
This place, for example, will do a custom bunk for $575, with proven materials and methods.
Or, you can pick an OEM pattern and have a pair of bunks ("wings") made for about $650-1,000.
https://www.bearcreekcanvas.com/Content/Pricing.cfmI just priced a few examples that I knew bed sizes for:
'91 Starcraft; queen/twin. $750
'99 Coleman; queen/double. $850
'82 Rockwood; twin/double. $850
The Rockwood might seem oddly expensive for less canvas. But I know that those bed canvases are individual panels, zipped together, rather than a single assembly of canopy and walls; and they (should) have triple-reinforcement around the edges, because they were screwed to the bed tray, body, and roof, rather than attached with a welt in a track.)
The Coleman, in addition to using a lot of material, has extra corner and canopy support reinforcement and triple-layered windows increasing its price: Fixed screen, zipped tinted plastic, and zipped canvas.
So some research would definitely be warranted, if you want to pick an OE design to order.