Cheers for the advice. We'll keep you updated with our adventures with it, i'm sure.
I probably have some thermal paste lying around from last time I upgraded my PC. They're very small units, so i'm not sure how much area i have to deal with for attaching heatsinks and how effective it'd be with that small area outputting up to 320A worth of heat. If we space things about wisely internally, we might end up with a bit of excess space to play about with some oversized heatsinks. If we can figure out between us all how to make these viable units, they'd be a very cheap alternative, if they can be made to not set themselves on fire faster than Diotoirs fur at high amps, if they do to begin with..