I'm with Darren, the return flow ones mentioned in the Hypergear thread has the return built into the end tank and is tight, the radius on the one picture isn't so bad, so while it has return flow piping, it's not a return flow cooler (if that makes sense?).
So in saying that to get rid of the "return flow" aspect you could have just replaced the piping, hard to say if the new piping will marry up nicely to the old cooler but it might not be far off?