With "most" modern aluminum radiators, the 2-row cores work just fine. Of course, a 3 or 4 row setup would be slick and offer more capacity, but I'm not sure it's needed unless you are already experiencing some heating issues.
Because they're using much larger tubes and different fins and have more dissipation through the tanks, aluminum radiators are not rated on the same size scale.
That Explorer (V6 manual trans) radiator that ransil is talking about is a very thin 2-row factory radiator with plastic side tanks and cools Broncos very well.
I'm not sure which version of the Champion more people are using though. Not sure I've ever heard anyone mention they were using a Champion 4-row, but it'd be good to hear some feedback if any one is.
Paul