Easier Way to Paint a Wall

Anyone who paints will tell you most of the job is the masking and prepping.  As I was thinking about painting a wall it came to light that not only the prep but the painting itself takes too long.  What I came up with is a tall (adjustable height) auto painter that has blocks on the bottom to prevent paint from getting on the carpet.  It would have large wheels on the floor and ceiling side and you would lock it into place so the wheels push off both to wedge the machine in.  Then you could have a metal or plastic plate that adjusts close up to the wall and block spray so you can paint without getting it on the carpet or ceiling.  Then running along the length of the bar that goes between the ceiling wheel and floor wheels you could have brushes, sprayers, etc. to dispense the paint.  It would need to be easy to move and set up or you might as well just spray the wall so you could have a handle to pick the machine up and move with just one guy.