For what you've described, you might want to look at the Bog Pod Extreme Shooting Rest and their tripods (or their Super Steady kit, which is tripod and two different rests).
I have one of their tripods, and their regular shooting rest, but have switched to a different set-up for my hunting needs.
Nearly all of my hunting is spot and stalk, and much of it is backpack hunting.
For a light, inexpensive, versatile option, you might want to consider using a Bushnell universal bino adapter on your tripod, which allows you to use your tripod for bino glassing and then immediately use it as a shooting rest.
The Bushnell universal bino tripod adapter costs less than $20 on amazon, and is a lightweight, fabric-covered,flat square, approx. 4x4", that mounts to a tripod via a quick release plate.
The bino adapter includes a buckled strap to hold binos onto the adapter - not the strongest, fail-safe system, but functional if you're reasonably careful.
I use my binos on the adapter for glassing, but then I can immediately pull the binos off and use my tripod as a solid shooting rest, because the 4x4" adapter is a flat plate.
I use a ball head on my tripod, so I can quickly and easily adjust the adapter to remain flat and level (for bino glassing or shooting).
And with a quick release plate on the bino adapter, I can quickly/easily switch between the bino adapter and my spotting scope.
For backpack hunting, I'm currently using a Slik Sprint 150 tripod (about $60 from B&H Photo). small and lightweight, but not as stable as a heavier tripod, of course.
For a sling, i'm currently using a TAB Gear sling, which has a detachable, adjustable loop that snugs around your bicep for stability, i.e., a potentially more refined, adjustable version of wrapping your arm into your sling.
Also, the back of the TAB Gear sling is about 4" of reinforced webbing, so that you can use it as an improvised rear rest when shooting prone.
One downside to the TAB Gear sling is that the large plastic QR buckle can be noisy, so I dampened the noise by putting some fuzzy-side Velcro on the outsides of the buckle.
good luck with your search.