"But I simply could not write non-fiction even if I wanted to."
It's really not as boring or bad as it sounds. Non fiction is not only far more rewarding and interesting, it can actually be easier to write. It is certainly easier to get into.
The problem is how we define non fiction. It doesn't necessarily mean "a boring old factual account of something". Non fiction has all kinds of different varieties and types, and most of them are fun, interesting, and outrageous.
You say "I can write a battle with destail going down to the tactics, formations, etc, and how a squad acts in a battle; complete with realistic and believable characters". Perfect!! Sounds like a great non fiction book!! It doesn't have to necessarily be based on reality. Create your own military strategy, go into details, make a long book about the strategy, and even put your own characters in it. I think it sounds like a winner.
Here are some non fiction books written by ordinary people that ALL are best sellers:
"How to Live with a Neurotic Dog", 60,000 copies sold.
"The World's Dumbest Criminals", 80,000 copies.
"The Quotable 'Star Wars'", 63,000 copies.
"Life's Little Frustration Book," 80,000 copies.
A non fiction book can also be a parody of a novel. "The Ditches of Edison County", which was a parody of "The Bridges of Madison County" sold 105,718 copies!
"The Duct Tape Book," 107,878.
"The Gift of the Jews," 200,000.
"Zip! Hop! Pop! and Other Fun Words to Say," 256,600.
"The Physics of Star Trek," over 100,000.
"The Truth is Out There: The Unofficial Third Season Guide to the X-Files," 103,000.
Could you have written any of these? All it takes is maybe a little research, and a good computer. And determination of course.
You love Israel. Why not a book about it? It's history. A guidebook. Or maybe the history of a certain city in Israel. Or something about the Jewish people. Thomas Cahill's "The Gift of the Jews" sold over 155,000 copies.
Very cool :) I would LOVE to write about Israel. However I would need first hand experiance of the place. Something I cannot afford.