I would think that the weight of the bags pulling on the ends of a carbon frame could cause a problem, especially if you hit bumps, bottom out or have any high pressure moments with the bike. I'm not sure and have never tried it, but what I do know about carbon makes me think this might not be a great idea.
Could you possibly rent a touring bike to see if you like it? Another option might be waiting for a good deal on a vintage one. If you get a good deal, you could always get your money back out of it later.