FWIW, I'm starting to think this (weight + comfort) is a problem with most military style packs. Take the Maxedition line for example. No internal frame. Even cheezy day packs have at least some supports to transfer weight to your hips.
I thought I'd point out that unlike most military packs, the Kifaru Marauder does indeed have an internal frame (I only found out about this recently). While it doesn't negate Matt's comments, I think it is a very importaint distinction because it makes the Marauder much more approprate for carrying heavy loads than most military style packs.
-john