Yes, they do exist. I have a whole team of full-stack developers. I gave one an iphone application to fix bugs in and convert from ios5 to ios7. He had no prior objective-c experience and in a week and a half, he had fixed all of the bugs and even dove into a 3rd party framework we were using to describe a problem to me using it with ios7.
A full-stack to me is somebody that can do web development, do server-side development, optimize SQL queries, understand security, scalability, and able to build linux server infrastructures for large software systems. They also are able to take any technology and provide value to a business using it in a matter of a couple of weeks.
A full-stack to me is somebody that can do web development, do server-side development, optimize SQL queries, understand security, scalability, and able to build linux server infrastructures for large software systems. They also are able to take any technology and provide value to a business using it in a matter of a couple of weeks.