The Gates foundation project for mosquito zapping AFAIK started in 2007 and still didn't get anywhere practical despite more than sufficient investment. http://en.wikipedia.org/wiki/Mosquito_laser#Implementations It's not so simple to make something that actually works and is cheap to build. In principle it can be as cheap as a DVD writer, but look, you wont have same effort put into this as DVD writer had. It's not so much about money as about having someone who'll actually work on the device productively. In programming there is this phenomena: good programmers are 5..10x more productive than average.
Regarding whose fault the world is, I meant that if it was my fault that other people are in hellhole, I would care more. For extreme example, consider some alien species whom are going extinct because they are extremely nasty to each other, they all are, not a single one is nice. In this case its basically 'their' fault.
With regards to the positive feeling-only motivated beings... how do you impose soft limit on joint movement for example upon damage of that joint? Make that being ecstatic happy except when the joint is off limits? I don't think this scales to all types of 'software' restrictions that needs to be imposed for survival. And even if it does, that state must be possible for evolution to arrive at, and must be reasonably stable when the species evolve further. Right now if someone is mutated not to feel pain, that person typically dies young even with all the intervention and help.
From Yvain's 'proposal' to measure money in dead children:
This makes sense to me, to a limited extent. You can spend money for your own benefit or to help others elsewhere, and there really are people who wouldn't have to die if you would forgo some luxuries. Making this tradeoff more explicit ("we're looking for an apartment costing no more than six dead children annually") might lead some people to greater generosity. It's a way of abstracting compassion.
Two things worry me, though. The first is that there's a big focus on spending here [2], but increasing earnings deserves more focus: getting a raise or a new job that added $10K to my salary would let me keep more children from dying than would reducing my spending on myself to zero. [3] The second is that thinking of all your purchases in terms of dead children is likely to make you miserable. Not just that, but miserable to little gain: you still probably spend almost as much money on yourself, you just feel more guilty about it. Much better, I think, is to pick a rule for how much to give and then apply it to money as it comes in. That way each purchase has no effect on the number of deaths you're averting.
(Note: I also posted this on my blog)
[1] The current number is probably closer to $2K.
[2] Maybe this is because it sounds weird to talk about salary in terms of dead children? ("I wonder what job earns me the most dead children?") Perhaps for earning the unit should be the "undead child"?
[3] In 2011 Julia and I lived on $18K for the two of us, not including taxes or health insurance.