I doubt there's a half size radiator that's out there that will be as efficient as a full size radiator. Even though it would have a thicker core, the reduced surface area would probably negate any benefits.
I found that Mishimoto makes a radiator for the Element (of all vehicles). It's fairly similar in size to my Accord radiator. The only difference would be how the fan shrouds mount. The Accord fan shroud is one piece for both fans, while the Element shrouds are 2 separate pieces. I'm waiting to hear back from Mishimoto with dimensions for the mounting points of the radiator. Hopefully they are close so I don't have to get much fabrication done to make it work. I'm not as concerned about using the stock fan shroud, as I will probably just have an aluminum one made to get a little extra room in my engine bay with some slim fans.