[17Again]

Derek, I'm a building AC guy, not automotive, but I'll throw some points to ponder out there.
While a bigger Condenser, Evaporator and Compressor, and more airflow will increase the capacity, you also have to take into consideration what metering device you need to have to make this all work. The refrigerant has to be metered throughout the system to ensure proper heat transfer is taking place. You can't just throw pieces in and hope they work, well maybe you can, but design engineers spend countless hours putting the pieces together to get a full functioning system. I think anything is possible if you have the time, money and ingenuity, it will all come down to trial and error until you have all the right components to accomplish this. That being said, I don't see why a combination known to work well in a larger vehicle couldn't work in a smaller one (space wise) as long as the necessary airflow and other parameters are followed. Just as a sidenote, utilizing R-22 which is the freon used primarily in home and building AC systems, you can also run a walk-in cooler at even lower temps by sizing the metering device to allow the refrigerant to boil off and change state from a liquid to a gas at the right point in the system. It is this process that creates the cold air and outlet temps that you are looking for.
Any engineers, or Dean want to elaborate further?

Rob