What if you used an old radiator with a 12v fan behind it and cycle the fuel trough it. I know it's more hardware and power consumption, but if you had a 12v pump as well, you could throw a couple of solar panels on your roof and let it do its thing.
I bought an oil cooling system fairly cheap if eBay to cool my water for meth recovery and that seems to work pretty well.

You did say you're going HiTech