Well as you can see in the thread you mentioned in the OP. I like the Eberlestock style backpacks, but I use mine for specialty needs, although you could use the scabbard as a compartment for a laptop.
This bag can hold a lot, I use it as my bug out bag
To give you an idea on how much it can hold i'll give you a run down on the things I have in it
Solar Powered battery charger, ipod.
8 AA and AAA batteries
100+ feet if 550 paracord
100 feet of fishing line,fishing hooks and tackle
first aid kit, band aids,quik clot, ace badges,asprin,burn cream,anti inflammatory pills, eye drops. tweezers
coleman camping stove with propane bottle
extra set of clothes. T-shirt,jeans,underwear and socks
garbage bags,tin foil,toilet paper,tooth paste, deodorant,tissue, shampoo,soap
signal mirror,whistle,flash light,
petroleum jelly soaked cotton balls,egg carton fire starters,lighter,water poof and storm proof matches,fire steel,small fire starting logs.
water personification iodide
2 cans of tuna,beans,oatmeal and kool-Aid
Tin cup and tin bowl
gerber freeman knife
camelbak 2 liter
*if needed two AR-15 mags and extra ammo*