My Kriega R30 backpack has that, its not that great for walking in my opinion but i can wear it all day on the motorcycle (that's what its made for), off the bike i usually have my pants and jacket and helmet hooked on the top of it so its very overweight.
Ah, so they do make them! Yes, that's what I meant, like those R35/R30 backpacks. Haven't seen that before, thanks for the link!
Do you mean sternum straps? They do make a big difference (especially when you have two laptops to carry!)
Yes! They also reduce unexpected side-to-side pack movement which helps to avoid losing balance when clambering over rough terrain.
I'm pining for extra straps lower on the front, so my everyday-backpack sits more snugly and swings around less, and the weight isn't on the shoulder joints. However, I also need to breathe, so dunno how to resolve all of that.