[alexandre_m]

Easy, but expensive way.

Are you really going to do this for all candidates that make it to the final round of interview?

Are you also going to compensate the time for the candidate if he doesn't get selected?

Unless what you're proposing is more a formality, and that unless the person doesn't show up he's guaranteed to get the job.

[ryandrake]

By the time someone gets to the on-site interview, the job should be "theirs to lose." You wouldn't be spending the cost of an on-site trip for every candidate that shows some promise during the distance interviews--you'd do it for those very few you're ready to give offers to already, but just want to double check a few in-person soft-skills things (and now, want to double check that he is who he says he is).