I'm for upping immigration quotas to help feed worker demand. Not just flinging open the border and allowing them full access to welfare/medicare/social security. Also, people willing to INVADE us in a criminal enterprise are NOT the kind of people we want coming here. Period.
My take on matching "willing worker with willing empoyer" is that there are no quotas, if a job opens and no one applies for it then it's gets advertised to the world. The official libertarian line is in full agreement with that and has been for years.
There are it appears differing opinions among libertarians about the wiseness of such a policy but the fundamental philosophy of the party is that free movement of people, even if it is to be done only at legal checkpoints and not through the backdoor is just fine.