I am an attorney in house at an oil and gas company. I'm lucky and we have a gym in our building that is free to employees, so when things are quiet on the work front it's really easy to slip down there over the lunch hour or sometime during the day. I have a really great boss who is really into fitness, so as long as I'm getting my work done he doesn't really care if I slip out in the afternoon to go.
One thing I do that helps make weight training more efficient and also give it a better cardio aspect is to do more like a weight circuit. It keeps your heart rate up and cuts the time down to do your program. So today, in 50 mins, I was able to get to the gym, change, do 5 mins of cardio to warm up, do a full body weight routine, rinse off in the shower, change and get back to my office. My standard cirucuits would be something like: Chest press, bicep curl, lunges (4 sets of 12 each), followed by: row (back), triceps, shoulder press (4 sets of 12 each). No breaks between exercises, and no breaks between sets (when possible). Then usually I do some type of core exercise, followed by a few stretches.
I hear you though, it's hard to fit it all in! I really feel like I need to add yoga back in this pregnancy, in hopes it will help keep me limber and because I miss it, but finding the time to do that is hard! I think also, that we (or at least I) tend to discount daily activities towards fitness. Like walking home from the train. Sure, it's only 15 mins but it's better than nothing and every little bit helps!