Maybe I'm crazy, but I have 2 5cuft chest freezers for fermentation so that I can ferment at different temps and cold crash no matter what else I have going. If you had one 7cuft for two batches then you'd either have to wait until they're both ready to cold crash or find a different place for one of them while you cold crash. Also, I like that my fermentor takes up almost all the space and that I can place the temp probe right on the fermentor. If you had two batches (I assume 5gal, I do 10gal and don't think I could fit 2 in a 7cuft) in a freezer and one was fermenting more vigorously then you might end up driving the temp too low or allowing it to go too high in one batch or the other.