It's common to cook a brisket via sous vide at 160 to 170 degrees. Note that unlike most smoking, the center of the brisket gets up to temp within a couple of hours and then is held there for many hours. It's "cooked" when it gets over about 140 degrees; it's tender when the connective tissue breaks down.
The main differences between sous vide and smoking (other than the smoke) is that hot air won't heat the brisket nearly as fast as hot water, and a brisket can't dry out as much in a vacuum sealed bag.
But the heat transfer rate only means it takes longer to get to temp. Once it's there it doesn't matter whether it is held in hot water or hot air.
If you wrap in foil, then it should retain moisture just like in a sous vide bag.
So if you are cooking at a really low temperature and if most of the time is spent denaturing the proteins, the only difference between cooking a little brisket vs. a big brisket is the time it takes to get up to temperature. Consider that...
I have no doubt it is possible. According to my projections the difference in time between 200 degrees and 175 degrees is huge. I expect it will take nearly 20 hours at 200 and almost 30 hours at 175. Sous vide briskets are commonly cooked for 24+ hrs.