As much as I hate the idea of not having a public option in the bill, what compromises will Republicans concede?
They don't want a public option in the bill.They don't even care for a co-op.
One compromise that was floated around early in the debate is the trigger option.  Progressives were anathema to that, citing it was a means to not only delay reform but kill it, and the trigger will never be triggered.  Is there any procedural way to make that trigger really work?  Such that Congress would have to legislate it, assuming certain targets were not reached?  Is it possible to set that in stone?  
I would be into supporting such a trigger option, if it can take away arguments from the GOP. Screw it.  If Republicans have their way, and no impact is made on costs, they've been proven wrong.  Once they're wrong, let's have it our way.  Can the American people wait 2-3 years for a public option?