[zoson]

While I'm all for increasing cooling capacity with simple methods, I have one major issue with designs like this. They take up too much space and as you noted, they weigh a ton. I'd like to see your grandmother try to pick that up and move it.
Secondly, I also see a problem with upkeep. Lets face it, most people today are not technically proficient, and are even afraid of computers. I would never give a layman a cooler like this, they wouldn't refill it (huge problem #1, run time) and they would probably kick/knock it over (goooooodbye computer).
Finally, cost. Filling a system like that with distilled water is definitely not cost effective, which means you're going to be dealing with corrosion and mineral deposits from your water supply. Nobody wants to take their system apart and scrub their blocks/clean their hoses.

I really don't want to seem like I'm raining on your parade, but the practicality of this solution is nowhere to be found.