Sorry, I got to looking over on Craigslist and found all sorts of tempting things to buy.
I used to wear a pair of revit cayenne pants for commuting. Those are not over pants and fit pretty snugly (damn Italians and their "euro fit"!) so when I was doing that I was keeping a collection of pants at the office. I switched to the Rocket overpants and that eliminated the need to change since I can get a medium in the ballistic pants over the top of khakis or jeans. The dual layering is warm enough for me (esp on the pani) that I don't need the insulation layer that came with the pants so I removed that and the hip/knee pads since that made them feel tight and hard to get on with the jeans/khakis underneath. I do keep a few pairs of shoes at work since I don't carry those back and forth. My morning would be: get dressed in work clothes, but with riding boots on. Put on overpants, jacket, gloves, balaclava, helmet, etc. Ride to work. Take stuff off (side zips on pants allow removal while fully dressed with boots on). Take off boots and put on one of the pairs of work shoes I keep in the office. I do still keep one extra pair of pants at work that stay here. Those are my "oh ...." pants that I use when I get rained on enough in the morning that it gets the pants under my overpants wet (hasn't happened in a couple years, but is possible in a wicked downpour since I removed the waterproof liner to make them easier to get on and off). They would also come in handy if I dropped a burrito in my lap.