Bottom line is this: the INS is not capabable of something on this scale, nor is any other federal government entity. The responsibility for making this, or any deportation scheme, is to place the responsibility on those who hire people.
Let's face it: the illegal immigrant problem is no different from the drug problem. The supply will continue so long as there is a market for it. As long as Americans are willing to hire illegal immigrants, there will be people willing to cross the border to be hired by them.
There's only one way to really put a stop to it: make it illegal to knowingly hire an illegal alien.
There was a time - back in the 60's and 70's - when there were frequent INS/BP raids on businesses that hired illegals. You'd read about them in the newpaper or sometime see coverage on TV news if it was big enough.
It's all a big scam and many pols know it. Not even the INS has a good, consistent way to check the authenticity of the documents, hence it will never work until we have a un-duplicatable ID card for all immigrants. If that does not happen, look for millions more invading America until Aztlan takes over the Western states as they claim they will soon do. Adios America-- Bienvenido Aztlan!