There are also servos that can go a full 360 deg. like the this one.http://www.pololu.com/catalog/product/522
Some call there continuous ones "360 degrees" .
I've gotten the parallax one to move somewhat like a stepper by giving a slight pulse foward (just past neutral) then an even slighter pulse backwards which makes it kind of do a step. By playing around with the pulse timing and doing the loop so many times I was able to pretty much get it to rotate a certain amount. A switch could be used to set zero.