what you could do, is get some liquid nitrogen, build a water chiller that works like the way ive described above, exept instead of using tecs, build a system to drip 1ml or less of LN into the water every so often. using a lagre quantity of water would spread out the effect - this is so that it doesnt instantly FREEZE your main loop, instead the water will get very cold, but not enough to damage anything. you will need lots of antifreeze in both loops this way.
I admit it may not be good enough for long term cooling, but it would make a nice machine for doing a one time bench, and should last longer than the limited normal ln benhces, where the ln freezes everything and damages it with moisture. imagine using sub -30 degree water/antifreeze/other mix, sounds good doesnt it
GLHF finding a suitable pump though :P