Maybe this is something the base would support?

President George Bush, in an effort to address conservatives’ dual concerns about border security and the rule of law, today said the revived immigration reform bill would finish the U.S.-Mexico border fence by fining illegal aliens to pay for it and requiring each one to build a section of the fence with his own hands.
[…]
“I hope this will satisfy my friends on the other side of the Republican aisle,” said Mr. Bush. “They’ll get their border security while those who broke our laws to get here will pay a financial price and serve time in hard labor to do a job that we can’t afford to hire Americans to do.”