i believe this has been talked about before, and they said it wouldn't work well. cold plates are designed around the fact that there will be ice directly contacted the heat exchanging surface. in a fridge, there is only a convective manner of taking heat away from the cold plate, not conductive, unless you were able to route the cooling lines around the cold plate or cooling coils which is generally impractical. convective heat exchange is not as effecient or effective as conductive heat exchange, so while the first beer or two may pour correctly, the more you pour, the worse it will become.
it's best to have the kegs inside the fridge, or the cold plate on ice.