several points:
on the general question at hand:
1. if you want to stem the flow of undocumented workers to the states, get employers to stop hiring them.
I agree 100% throw a few CEOs behind bars and that will stop real fast
2. but in these days of cowboy capitalism, employers find it to be just find to drive wages down to the lowest possible level (cost-cutting, dontcha know) so am not sure how you would do the above exactly.
Have severe penalties for illegal hiring
3. undocumented status for workers has political consequences as well--it more or less guarantees an atomized, powerless workforce, one not likely to organize itself because of the ways in which undocumented status is understood. this works out for the maintenance of political control in a number of cali-cities.
I do not understand?
4. it is also typical of these days of cowboy capitalism that people "concerned" about the matter of undocumented workers would be more inclined to blame the workers than look to firms, which drive the economic cycle that draws people to find work here in the first place.
I agree, we should not throw all the blame on the workers, 'you make me laugh with the cowboy capitalism remark! 
5. it is also interesting that no attention seems to be paid to the outflows of this population--it is not obvious that undocumented workers come to stay in the states in any number statistically speaking. but it seems not to matter for the--largely rightwing--ideologues who manipulate the political matters surrounding this issue to create a sense of beleagured national solidarity, which is crucial to mobilizing people in a rightwing direction.
You might check out this site http://www.capsweb.org/
it is a mix of environmentalists / population control freaks
on crime stats:
6. police stats on this kind of issue should be viewed with great suspicion, particularly those from la, given the glorious history of racism institutionalised by that department.
Doesn't sound like you are a real supporter of the LAPD! Until recently they had a black police chief for several years
7. even if the stats cited above are not problematic (an argument would have to be made for that--i do not buy the idea a priori), the logic behind them would seem to militate for an easing or elimination of undocumented status--which would in principle tend to drive wages up--which would reduce the levels of poverty--and would make these workers part of a political process for defense of their own interests--which would perhaps eliminate some of the incentives to organize for their own defense on other grounds.
it seems to me that you cannot have it both ways--if you are inclined to uncritically cheerlead for this variant of capitalism, you have nothing to say about undocumented workers as such--who are human beings drawn to the states for work because employers find it in their economic interests to hire them. conversely, if you have some kind of problem with undocumented workers, it forces you directly into a critique of this variant of capitalism--if it does not, then what you have to say is incoherent.