Trust me, there is a LOT more red tape when dealing with the FAA.... Especially with a ride that tall... Height, colors, location, etc etc etc.... I aint sayin I know something, cuz I dont, I know of a group of people who couldnt build a building near a small community airport b/c of the color of the brick.... petty I know...
Personally, when that majical announcement day does come,(if it ever does) I wouldn't look for a ride much over 200'.... This whole thing is hearsay anyhow.... but it is fun to speculate..

Wouldn't a 300' hyper rock!!!!
