Using tortillas instead of bread can entice even the pickiest eaters to dig in to their sandwich. I started using tortillas some time ago when we went on a road trip. They stayed together and looked better longer than sandwiches made traditionally with two pieces of bread. The burrito-style sandwiches also were quite easy to eat in the car.
You can get many different varieties of tortillas now, including sundried-tomato and whole wheat. Do some exploring and see what you can come up with, too!