Cold plates work remarkably well. I have a 2 tapper that I use on trips or parties at friends. Cools room temp beer to consumption temp very nicely. The other benefit to the cold plate is that it lays in the bottom of the cooler and you can use the ice to store other beverages like bottled beer, white wine, etc.
For what it's worth, the 28 qt Coleman coolers work perfect to hold a two channel cold plate. They come with a carry handle too.