A.,
Cheese is good for them, as well as crackers. Anything you might put on crackers too, would be good.
Maybe an avocado dip?
Veggie spears for the older, veggie shapes for the younger (circles - carrots, triangles and arcs - cucumbers, cheese squares, radish half moons, you get the idea)
Also, soynut butter and jelly 'dips' for crackers would be fun too, I think.
You might have to try these out at home to get them used to them, then maybe they would request them for their lunches? :)
If they are eating lunch meats (not saying they should - another story, you could try 'roll ups' with cheese.
Rolls might be an alternative too, to get them a little bread in their diet (don't think it's necessary, but hey!)
Really, anything you might eat at home, in different shapes and sizes, takes on a new persona when at school - other kids don't have this stuff. :)
Good LUck,
M.