What do you think about the type that most people run now - the general, large front mount intercoolers that are 15" tall with the inlets running directly facing into the core, either at the top, middle, or bottom (don't think it matters)? Pull off half those tubes and you've probably got a more efficient (size-to-cooling/flow) intercooler. In fact, I love(d) my Porsche 944 intercooler that was a 6"X6" block that was about 20" long and, with the end-tank design, uses the entire intercooler efficiently. Just sold it today to a turbocharged '75 Stingray running straight propane
I hardly understand fluids, but I'm thinking most of the bottom of those intercoolers don't get used at all. However, I think if the end tank inlet is aimed in such a way as to direct the air down perpendicular to the tubes, then that is much more efficient. I'm thinking asymmetrical end tanks are the way to go, by the way.
EDIT: check out http://www.bellintercoolers.com/ and their end-tank designs and consider what MONZTER has shown us. Lots of funky end-tanks: asymmetrical, dual-inlet-single-outlet (vice-versa?), sticking with shorter but thicker cores(?)
EDIT AGAIN: What effect would simply flipping one end-tank on MONZTER's intercooler (minus the splitters) have on flow, efficiency, turbulence?