Jennifer
When i make them use pretty much anything at hand!! The trick is to cut the veges into very thin strips other wise they will be too crunchy!! Use carrots, capsicum, bean sprouts, onion, mushrooms, cooked lentils, punkin (mashed), peas etc you get the picture, mix in some soy sauce and an egg to keep it all together!! then roll and bake. Remember also to turn often or use a good non stick pan!! As i said before ..... It takes lotza practice :0)