I've made some pretty tasty fried okra using soy flour and lots of poultry seasoning. I'm not a big fan of soy but you only use a little and it does brown and get crispy, and doesn't taste like soy at all as long as you use a lot of seasoning. That could work for green tomatoes too.

Beat an egg with a little water, dip the slices in, then coat both sides with heavily seasoned soy flour and fry in hot oil.

Also, it's very important that the oil be hot enough before you fry. If it's too cool then it will get soggy. On the other hand if it's too hot then it will scorch very fast. So it has to be hot but not smoking.

This works for onion slices too!