The trail bar problem is simply bulk. Because they are square. Anything square does not pack in a round canister very well. If you are willing to squish them into unrecognizable blobs, the problem is solved! Fruit and nut trail mixes really pack down better. On my 7-day trip I have room in the bear canister to use trail bars, but for a 10-day trip, I do not. Like Pika said, a pin-prick in any packaging will help it pack better.

My favorite soup is Kikoman Miso soup. It is super-light and has freeze-dried tofu. I also buy a pack of the dried seaweed (used in shushi) and add these to fortify the soup (I happen to like the taste of seaweed). Only problem is that it is expensive. I found the soup at WalMart for a good price. I live where there is a large Asian population so our stores stock a lot of Asian food. Not sure every WalMart would have it. I also buy large bulk bags of soup and pack individual servings in snack-sized zip-lock bags. Look in the soup section of any large supermarket. I like the cheese-brocolli soup. Just be sure to read the label so that it does not require a long cook time. Whole Foods also has a lot of dry soups in their bulk food bins.

Oh- another trick. With zip-lock bags, you can also get lots of air trapped inside. When you close the bag, just before finally locking, squish out all the air. I have also used a straw and sucked out all the air before sealing. The interesting thing is that any bag of food will pack better if it remains flexible. There are freeze-dried food that are shrink-wrapped in solid blocks and these do not pack well - leave too much air space.