I've been trying to add in a few simpler bentos that look awesome without taking a ton of extra work on the part of the maker. I'm thinking that a simple little cheese critter might be one of the best ways to make a box look really cute without investing a ton of time in its creation.
This little giraffe only took a minute or two--two colors of cheese, a cookie cutter, a sugar eye, a straw to make the spots, and a teeny dab of cream cheese (think toothpick dots of cream cheese) to make it stick.
This box holds a couple of mini pita bread sandwiches (roast beef & white cheddar), topped with a cheese giraffe. The giraffe is stuck to the top sandwich with a couple of dots of cream cheese, just like his eye & spots are stuck on him. The other compartments hold a mini muffin & carrot sticks, honeydew and watermelon.
The box is a 4-compartment Lock&Lock container that I don't use often but always think I should. It's a great bento beginner box since it has separate inside pieces. They aren't 100% airtight, but Press & Seal can help if you use a container for something like yogurt. I bought mine at Target, but 3 years ago. I'm pretty sure they are available online, I'd check your local stores & see first.