Slight tangent, but still on the same topic.. started looking at heatercores and came across
this monstrosity. It's an 11-3/4"x11"x3/4" transmission cooler that mounts similarly to the Swiftech 676 (except this unit being much larger in surface area).
For someone building an external cooling unit this could be an interesting part.. imagine an entire side of an enclosure with this being the most dominant feature. This, and the required ancilliary equipment (pump, reservoir, fans), could probably be crammed into a 6" wide, 13" tall, 13" deep enclosure by my best estimates. Maybe even smaller depending on the components selected. Mounted next to a window or an A/C unit, the performance of this unit could be surprising if the flow restrictions aren't horrendous.