Here is a crane (But they come in all sizes)
This is your basic dolly (this is obviously on a flat straight track, you can usually bend the track and add shims to adjust for ground uneveness), there is also such a thing as a field or doorway dolly:
This is a guy who oddly enough looks a lot like me using a glide cam pro model which is very similar to a steady cam
Here's our favorite guy with his "poor man's steadycam"
There are of course other models/brands in these levels but its important to see that all of these devices are different and accomplish different kinds of shots. If you try to use one for the other chances are it will be a comprimise if you can even pull it off.
In Chris Gore's book, he has an awesome idea:
............FAST
GOOD..............INEXPENSIVE
Any solution you can come up with for anything when in any phase of the movie making process (and really life in general) 99.9% will only have two of those three items to it. In other words, you can have a solution that is fast and good, but it won't be expensive.. try it with the other ones.
And although my device which I will be selling shortly does not have counterweights, it is possible to acheive a balanced shot, it certainly removes all camera shake, and is much less expensive than most other devices out there. It also allows you to shoot in very tight spaces and weighs very little.