I like the idea, and would definitely buy a copy. I am not a marketing expert but it seems to me that Vegas junkies would buy the book, as well as some casino employees.
As an admitted Vegas junkie (and previous Vegas casino employee) I know some of my favorite websites are the ones with stories submitted by cabbies, dealers, and cocktail servers. You are absolutely correct that the front-line workers are the ones who make the wheels in Vegas turn. They also have the most interesting stories, and would likely be happy to share. I always enjoyed talking with my co-workers about our backgrounds and our paths to Las Vegas. I worked surveillance at two major strip properties in the 90's alongside people from across the country and around the world. Very few were born or raised in Vegas. Very few ever planned on working surveillance in Vegas. Some had truly amazing stories.
You will have to spend a lot of time finding and interviewing people, but the end result could be a great read!