For protein in lunches and heartier snacks our go-to things are cheese, hardboiled eggs, black beans, nitrate-free low sodium lunchmeat (ham or turkey) and yogurt - my kids love the new "simply gogurt" squeeze tubes, but we usually do the plain old giant tub of vanilla yogurt plus berries and/or bananas if we're eating at home.
I think it would be hard to store bento boxes for the whole week, honestly. I pack DD1's bento lunch in the morning instead of the night before because I don't want things to get mushy or run into each other. But for her lunch (which isn't that much bigger than a hearty snack) I pack things like:
A mini flatbread roll-up with cream cheese and ham, sliced into pinwheels or sunbutter & jam on a mini bagel or regular bread (frozen works well if you're preparing it in advance, the jam doesn't soak into the bread and it's thawed by lunchtime - apparently you can also freeze the whole pb&j sandwich pre-made, but I haven't tried it yet.)
- with -
sliced grapes or raspberries or raisins & craisins or cubed apple or pear or a peeled clementine
- plus some combination of -
sugar snap peas, baby carrots (halved lengthwise), leftover cooked veggies, olives, grape tomatoes, frozen peas (my children are weird and love these)
- and -
a few goldfish or letter pretzels and a couple of small vanilla wafer cookies.
Sometimes I toss a squeeze tube of yogurt in there, sometimes I do rice and beans instead of the sandwich.
DD2's favorite "snack" for a long time was black beans, diced colby jack cheese, frozen peas (sigh...yes, frozen) and puffed rice cereal. (Who am I kidding, she still loves all those things!)
Oh! And I just remembered, we used this Sassy container a lot for when we'd go out to eat and want to bring baby-friendly table food for DD2:
http://www.amazon.com/gp/product/B00...ef=oss_product
You might be able to do those a few days in advance, since the containers are all separate, but you'd probably want to keep the containers of grain type things out of the fridge to avoid them getting soggy (unless it's something like rice that needs to be refrigerated, of course!)
HTH!
Sarah