Here's some help:
Take 2 of these:
Swiftech MCR220-QP Liquid Cooler Radiator
Swiftech MCR320-QP Quiet Power radiator
1 goes inside the cooler water, the other goes inside the aquarium.
Get a decent pump (Mad Drive 3 or equivalent would probably work). You need 1-3 GPM
(60-180gpH) actual flow through the rad.
1/2" ID tubing
Create a closed loop: rad>pump>rad.
You will need a powerhead or small pump (via aqua 480?) to create flow through the cooler rad fins. The rad in the aquarium may get enough flow just from the aquarium circulation--maybe not--may need another pump for that. You may be able to get by without the additional powerhead(s), but the system would have to be setup to check that out.
Understand that the warmest source (most heat) will cool. In other words, If you forget to add ice to your cooler and for some reason it gets warmer then your aquarium--the setup will then begin to heat your aquarium, not cool it. As long as the cooler water is cooler than the aquarium--it will continue to cool the aquarium.
How much cooling will you get? I don't know, but the rads will work much better then the pipe. Most people are really only looking for a few degrees of cooling, so something like this is possible--but its still not cheap: Cooler, pump, 1-2 powerheads, tubing, fittings, space, labor.
If you are interested in actually doing this--let me know and I'll help you get it sorted out.