I can tell you that the 3.5 chest freezer I have (which has the compressor step inside) will only fit one corny keg width-wise in the remaining area, along with the 5# CO2 tank. I was deeply disappointed when I tried to fit two cornies in there (I was using the freezer as a fermentation chamber prior to making it a keezer). I have a 6" collar on the top...and even with that...not wide enough for side-by-side cornies.
I am waiting on a buddie's used refrigerator, which I plan to use as a keezer. My current keezer will then revert back to a fermentation chamber...haha.
All that being said, I advise my buddies who brew to take the equipment, cornies, etc. with them when they buy fridges, freezers, and whatnot to check fittings before buying and then finding out the measurements don't pan out. I know it might seem odd to walk into HD or a box store with a corny keg...but hey...who cares?
Cheers!