Dave,
Funny you should say that, years ago I came up with series of designs based around a powered rotor gyro concept. They ranged in size from a single seat seat proof of concept to a three seat version and finally a 6-8 seat version. One scenario I envisioned was a high speed dash to target, a decelerating pop-up to an unpowered decent to target. Never got much beyond the initial design stage but I find it interesting that Eurocopter's compound is most similar in concept.
In recent years I've morphed those ideas into a UAV concept but alas I fear I've become too much of a libertarian to pursue it much beyond the concept stage.
Anyway, as Shawn has alluded to, there have been rumors for years about black budget helicopter projects. I for one would love to hear from others what sort of things have been swirling around the rumor mill.
Here's what I've heard over the years.
The mysterious single seat, faceted, notar, simitar shaped rotor, retractable gear and gun ship seen at unnamed military test sites. Testors possibly made a model of this years ago?
The rumor that Sikorsky's stopped rotor (X-wing) research project was cover for construction of one or more black budget examples.
Both of the above were referenced in an early 90's article in Aviation Leak.
From personel interaction:
The rumor of Notar equiped AH-64's being seen in the UK confirmed to me by a former company employee.
500 style UAV being operated from Albania along the border/into Serbia in the mid 90's by work associates.
Being told by a friend and former Ranger that aircraft were operating in central and south America that were lie nothing he had ever seen?
Alright, give it up gang, what have you seen/heard of? As Shawn said this is a rumor network afterall...