A something else is possible if you have a locker or other storage space at work. Some folks drive their stuff in at the beginning of the week, then drive it home at the end. Or they'll drive in on the weekend to make the exchange.

I do something similar, but with bikes. On Mondays I use panniers to carry in the week's worth of work clothes, lunches and snacks (and library books). On Thursdays I use the panniers to haul home the laundry (and library books). On Tuesdays and Wednesdays I can ride any bike I want without having to haul anything.

Even if you have to haul stuff daily, a full blown tourer probably isn't necessary. Last I checked, all the entry-level road bikes from the major manufacturers had rack and fender mounts. They're perfectly fine for light-duty hauling on commutes, and a bit livelier than most touring bikes.

In the end, I still favor the multiple bike solution. It's nice having spare that can be pressed into service in either direction--on the commute, or on weekend rides.