I recently picked up a x-ufo from thinkgeek, which I've taken a picture of for your enjoyment. These are very fun, cheapish (180$) 4 axis helicopters. Thier construction is fascinating. You might remember a previous, weird, post I did about gyros. I complained that mechanical gyros stink and should be replaced. Well, I was talking about this one. I had a minor (my fault, I assure you) crash that resulted in the gyro, well, shattering, and without a gyro these things are impossible to fly. I ordered two new ones from an outfit in Utah and recieved them last week. Installed the new one and got a good look at the damage I did to the old one.
Some interesting things about the X-UFO. Its construction is pretty labor intensive. Lots of little parts, screws, multiple circuit boards, it is a testament to just how cheap Chinese labor can be. If you were designing it for local contract manufacturing, you might have opted for a single board solution with a mems or piezo gyro. Things to note include the cheap plastic gimbal housing, the super fine copper power wires to the internal motorized flywheel. The weird thing about this gyro is that it doesn't really work all that well past about 30° and the electronics assumes that you are inverted and tries to right the copter.
Of course, this is how I ended up driving the x-ufo into the ground from about a 25 foot hover. Oops. Anyhow, its a really cool toy, but I think if you buy one, you should try to pick one up with an electronic gyro. Click on the pictures for more fine details. Note that the gyro boards piggyback on the actual board and thus might be replacable with a different system, in theory. In practice, there is a reason I bought two replacement gyros.
Anyhow, check out the pics, the person who designed the copter really was quite the hacker. Note the washer as a flywheel.