If tough is what you seek. Search out anything made by Dana Gleason.
His current company Mystery Ranch supplies tough packs for tough applications.
I have the 3DAP, it fits well into the tough category. I would not hesitate to use it as my BOB or INCH or what ever the cool term is this year. Solid kit.
But in truth, every pack he has ever made fits that category. Look to the Auction site for Dana Designs. I used a bomb pack in a previous life with great success. And I had its larger brother the Bighorn set up as a S.A.R. Pack.
The terraplane is probably too large for your needs. But back then Dana made tough packs that carried their model name and the term Overkill after it. They were super tough. And can be had for a song sometimes. If my life depended on it. I'd rather have a used Dana pack than most of the new ones I have seen.
One thing to keep in mind. With strength comes weight. Dana packs can feel heavy, even when empty. But his suspension works wonders. The weight of the pack and the heavy junk you will load in it just disappears when it is on.
For equally tough and equally expensive options. Look to Kifaru and Hill People Gear. MR, Kifaru, and HPG are all expensive. But they are quality gear made right here in the U.S.A.
Another option is Tactical Tailor. Also have a look at the Karrimor Sabre line of packs. The Sabre 45 is regarded as a togh pakc by tough folks. At present I believe it is being made here in the states by Tactical Tailor.
Right now, the Sabre 45 is about the only pack that I could see surrendering my 3DAP for.
Some day I may build out a HPG Ute or Lindi they are quite modular in the design.