Well it's not really "survivalist looking" but, it's the one I use and the best looking one imo. It fits with every armor and also has a strap, wich most backpacks don't have.
It's the "Die Hard Bag" from "The Couriers Cache" mod by Dragbody.
You can get it here:
https://www.nexusmods.com/newvegas/mods/49531