Yes! Well, sort of… You’ll need to get a 13x2 female header that has long enough pins as to allow a board to plug into it. I don’t think the ones SparkFun sells (below in Related Products) will do the trick. What I ended up using was one of Adafruit’s 13x2 Extra Tall Stacking Headers, which have 9.2mm long pins. They’re designed to have a 1.2mm PCB stack on top of them, so the boards would’t sit flush when I plugged them in; which I fixed by cutting 1.8mm off all the pins (making them all 7mm).
Now I can keep my Pi safe and still keep the expansion boards on the outside, where I can actually work on them! It’s funny, I’ve been searching for a case that would allow me to do this for quite awhile and it turns out the solution was one of (if not the) most inexpensive products on the market.
Here’s a quick collage showing the case and various boards installed (RaspyJuice RevA, PiFace Digital, Raspberry Icing and a AdaFruit Proto Pi Plate): https://twitter.com/TimothyBrown/status/328382662408564736