Actually, a lot of people have long arm machine setups for doing just their own quilting. It's becoming more and more common. Many people who have tried to take in quilting jobs as a business quit because it can be frustrating when people bring in tops that don't lie flat, are crooked, have weak seams, etc.
For lots of information and advice, try joining the homequiltingsystems group at
http://groups.yahoo.com . Quilters have all different kinds of setups depending on what kind of quilts they do, how much room space they have, how much money they can spend, etc. I'm not sure, but it seems to me that most of the quilters there use long-arms just for their own quilting.