Are you sure about that? Mine only extends a few inches from the radius of the carboy.
As a NYC small-apartment homebrewer (note my username

), one of the best non-standard purchases I ever made was a 40-quart aluminum pot at one of those restaurant supply places in Chinatown. I use it both as a brewpot and as a swamp cooler for the fermentation. As a brewpot it extends over all four burners on my tiny oven, vastly increasing the quality of the boil (it does require full-volume boils; evaporation is of course higher given the higher surface area relative to more conventional brewpots). After the wort is in the carboy I clean the pot and put the carboy into it, then fill the pot most of the way with water. I regulate temperature with ice packs I made from old bottled-water bottles. Be sure to throw some iodopher in the cooling water or nasty things will grow during your fermentation.
There are some special care instructions before you use aluminum as a brewpot so you'll want to pay attention to those if you go that route. But even if you don't I'd be surprised that you don't have even a couple inches on each side to fit one of these pots for cooling.