Republicans have been promoting a payroll tax holiday for a while now. Ezra Klein did some reporting on whether they'd make a deal on that issue now:

From my reporting, the problem wouldn't be in the White House. It would be in Congress. I've asked a number of Republican offices whether they'd be willing to work with the Democrats on a payroll-tax holiday. Without fail, they've told me no, that they no longer support a payroll-tax holiday given the size of the deficit.

You have to keep in mind that the main role of most Republican alternative proposals has merely been to stave off the accusation that Republicans have no plan of their own. And it's certainly true that Republicans do have some ideas, it's just that those ideas -- like the Ryan Roadmap -- are radical and unpopular and Republicans don't want to run on them. When you see Republicans put forward something more concrete, it's an offer likely to be withdrawn if taken up.