Ebay in most countries lists "water coolers" and "office water chillers" for auction. You can also pick up these little lovelies from liquidators who sell off assets of failed companies. A 100W water chiller (which uses a phase change refrigeration system, like your fridge does) can typically be had for $70USD, perhaps less if your timing is right. While the compressor is generally rated at greater than 100W, the condensor/radiator on such office units tend to be the limiting factor on the unit's colling capability, and if you have a vacuum pump and are prepared to purchase some HVAC hoses and a bullet piercing valve, you can refit such a unit with a higher efficiency condensor, and run it at the compressor's maximum rating. A unit thus converted is more than ample for 400mm column, and will recirculate ~2°C water indefinitely with ambient temperature above 40°C.
Phase change coolers are far more efficient than peltier coolers, and tend to be higher capacity as well, but if efficiency isn't an issue, then a high wattage peltier water chiller is probably also perfectly acceptable.