What about slice (like zucchini slice)?
Or a little "nacho" mix or salsa which might be a mix of beans, avacado, celery, corn kernals etc which can be on its own or with something to put it on like rice crackers or pita bread.
You could make salads as well - coleslaw, potato salad, pasta salad.
Pastry triangles filled with whatever fillings you like.
I personally hated sandwiches as a kid so I would take Salada's with vegemite or butter or honey.
If i wanted to take something that should be kept cool, I would throw a fruit box in the freezer the night before and by the time lunch came around it was defrosted but still cold and my lunch hadn't spoilt.
You could pop in a variety of cold cuts and cheese etc.
What about chicken drummetts if she likes those? You could wrap the leg bit in foil or something so it is less messy and she can hold that to eat them. When my sister was living with me I still did that for her and she was 17! I would cook a batch of terriyaki or similar chicken drummets and she would have the left overs like that for school the next day!
I like the idea of mini quiches!
I liked sending my sister with various home made dampers (cheese and chive, bacon and cheese etc). They didn't have to be big, I would make the batch into smaller segments before cooking.
What about cheese and bacon rolls? You know the ones you can get from the supermarket and Baker's Delight?
Or her foccacia

When school "goes back" next year, look for the food mags like SFI - they always have some good ideas in them for school lunches!

HTH

MG