P,
I'm sure it could be done, but I would think the disadvantages would outweigh any possible advantages. At this point I can't see any advantages.
For it to look good, I would think that all the plumbing would have to be inside the gunite shell.
The shell would have to be stronger, because it would not have the ground as a supporting feature.
You'd have to build a deck around most of it unless you just wanted to be able to get in and out at one spot.
The sides would have to be covered in something.. Rock, tile, ??, which would add to the cost.
Just to build it you'd have to construct a form of some type. The ground becomes the "form" for an normal in-ground pool.
There may be a ton of advantages, but I'm not sure what they would be. Let's see if we get some more comments...
Why would you want to do this and what advantages do you see?
Thanks for posting,
Jim R.