I don't have any experience with the EMR, but I used the Dana Designs Astralplane Overkill (before DD was bought by K2 and moved to Mexico and when it was still owned by Dana Gleason) when I was in the military and I've loaded it to well over a hundred pounds and it carried relatively comfortably for the amount of weight (more comfortably than any other pack I've carried with that much weight). It clings to your back like a scared baby monkey and you can adjust the weight easily from hips to shoulders and back, as needed. It also has 4 ways to get into the main pack, making it great for access. I've used it all over the world when guiding and it's held up to the tests of military use and alpine climbing. The Overkill version is 1000D cordura. It's a heavy beast, though.
I think they dropped the Astralplane, but still make the Terraplane, which is a smaller (still big) version.
Dana Gleason started Mystery Ranch backpacks and has this design in the G6000, G7000, CBMR's, NICE 6500, Kodiak and the Grizzly. With out without military flavors, if that's your Kool-aid.