At my hunting camp we've built some elevated platforms like you've shown in the first picture then put a pop-up blind like the primos double bull on top of them. Screw some eyelets into the platform and use big zip ties to anchor them to the platform. Put a folding canvas chair inside and hunt in comfort, I've even been known to take a portable buddy heater into them. At the end of the season cut the zip ties and take the blind down for storage until next year. It works great.
