A candidate meeting your criteria will be a ways off.
I can think of several that I would like to see run that I think could win the GOP nod, but probably won't. The best of the bunch would be Jeff Sessions. James Inhofe and Sam Brownback are also good. In the house, Mike Pence and JD Heyworth come to mind.
And any of these guys would take out McCain or Rudy, IMO. There will definitely be a conservative in the race and its better for him not to announce yet anyway.
Probably never. I favor a candidate who believes in the constitution and will sacrifice his/her career and even his/her life to defend it.
I know of no liberal or conservative, Republican or Democrat who is willing to do that, or even wants to.