I quit smoking 11 months ago, and I've only been low-carbing for a few months so I'm not an expert on the combination. But I had to chime in and say: good for you!! Quitting smoking is so hard, but so worth it!! And I think if you start low carb eating at the same time, it will give you something to focus on and take your mind off smoking. You have to research and plan and find recipes and you'll be too preoccupied to obsess over smoking. Sounds like it would work to me!
Best of luck to you, and keep the quit! (By the way, I used the free forums at quitnet.com for support while quitting; reading and posting really helped while in the thick of withdrawal hell).