Causurina equisettifolia. Horse tail tree. In the right circumstances can grow 80-90 feet in 10 years. It's used in eriosion control along beaches and also used in bonsai. but it is a tropical and requires all the light, heat, and humidity you can give it. Many tropicals in the right circumstances will take off like rockets, but it really boils down to practicality for me. I live in the chicago area and without any special lighting systems my ficus' aren't performing now like they were in summer. It makes me consider what many other's in my bonsai club have already done and that is stick with what grows best in your area. I'm not quite there yet though. I look forward to seeing what other's will suggest. Good luck - G