RE: Metalstorm.As they can be made e-specific to one owner,I think we should all be able to have a liscenced version along with stingers in case rouge airliners get loose in our skies. An acquaintance has come up with what he thinks is a novel and practical design for a liquid propellent rocket engine. Although his initial tests were not conclusive he thinks he can build an under 50 lb LOX-Propane rocket which can put 20 lbs or more into LEO. See http://www.halfwaytoanywhere.com/rocket/ Interestingly, he found that ordinary plastic quart size Coke bottles (esp. the rounded bottom types often capped with a black base) were very flexible at LOX temperatures and were able to withstand enough pressure to make them practical as fuel and oxidizer tanks. The ISP is greater than 300 and Mass Ratio even more impressive. If he can get some funding an amateur single-stage to orbit is a very real possibility. It could also have a variety of commercial and military uses ;-)