That's an interesting setup! Can't say I've seen anything quite like it.
I never got around to getting the cold smoker because ever since I smoked our first fatty, that's what my wife wants to have the most. Of course, you smoke those hot, like a pork butt, and I do them with my MES set to 235.
Basically, in that setup your MES is doing nothing but allowing the smoke to expand and cool off a bit more, then diffuse into the upper box. You could replace the MES with another, bigger, cardboard box, or a galvanized trash can, or just about anything.
Thank you Bob, I don't see why you wouldn't be able to use another chamber instead of the MES.
I do want to make sure to mention that I use this setup (minus the cardboard box) for hot smokes too. It cleans up the smoke before it touches the meat during long smokes, what is reverently referred to as Thin Blue Smoke. However, on shorter hot smokes I'll remove it to use without pipe or just the chip tray for immediate exposure to a lot of white smoke. Its two different techniques (strategies) I've learned on this forum.
I recommend reading the following threads if you are interested in different "smoke" techniques. A lot is personal preference, but you cannot ignore the science!
Good luck! Let me know if you need anything!