Once such a system is developed and in place, you can them prosecute employers for not checking.
Currently, everyone that we try to prosecute just claims ignorance. There is no way to check immigration status and they are not fraudulent document experts, and even a bad lawyer can get them off the hook. That is why there is no enforcement now. INS (now ICE) has spent millions upon millions of dollars trying to prosecute employers and they always lose.
Once an easy system is in place and enforceable, then we can prosecute and only then will employers be motivated enough to hire legal aliens.
Any guess worker program that happens before the above will fail, as very few or no employer will hire a person that cost them more to employee and has other rights over a person that is cheap, has no rights and is easily replaceable.
My first inclination was to say "YOU DREAM", or "IF IT SOUNDS TOO GOOD TO BE TRUE, IT USUALLY IS", but after reading your bio I want to thank you MI for your service,
and with your experience, I'd like to see you somewhere high up in the program if it is adopted. Gods speed.