Another option that I have used before is doggy daycare. I mean I don't think it's reasonable/cost effective to do it everyday, but if you plan on doing litterbox/pad training it may be an option just so he/she gets socialized.
However, if you did get a little one and he/she was home by her/himself for a long period of time, keep in mind that no matter how tired you'll be from your long day at work, you'll still have this little ball of energy that will demand your attention!
