I've wanted a left-side number pad for a long time. I've contended that (for right-handed people) having a number pad on the right is poor ergonomics. If I centered such a keyboard in front of me, then the number pad would be in the way of my mouse. So I end up offsetting the keyboard several inches to the left, which causes me to have to position my arms awkwardly in order to reach the letters. I ended up using keyboards with no number pads at all (in my case a Leopold FC660C).