I also started reading about steppers with position encoders built in and that got my attention since it might allow me to skip the initialization and simply drive the stepper to the correct position at any point in time. However, I'm not finding any Arduino sketches or projects that leverage this position encoder functionality.
But there is a lot posted on using quadrature encoders which is just the input side of your stepper/encoder assembly. The problem with simple 2 channel encoders is that on power up there is no way for the encoder to tell you the specific starting point of the shaft, it just allows one to count steps up or down once you do command the stepper to move in one direction or the other. Often a design will have a optical gate at one extreme end of travel and your start-up code will move the sensor towards that direction until it detects that end of travel stop and thereafter you can just keep track of step counts to determine where you are in the full travel range.
Lefty