The Smokies in December
Yes, the road to Clingman's Dome is closed from the first weekend in November until the middle of March. The road over the Smokies between Gatlinburg and Cherokee, NC, is kept open except during inclement weather. Since they don't apply salt to the roads (said it will damage the environment... it might kill a salamander next spring?), the road is usually closed anytime the park has ice, or snow accumulation of more than an inch or so.
It's really fun to be at Newfound Gap, the highest point you can visit during the winter, when the snow comes. They close the park to incoming traffic, but if you're already there, hey, you can take your sweet time leaving! Talk about some great photo opportunities playing in a foot of snow. I know that doesn't compare for our buddies up north, but for these parts, that a reason to celebrate.
Stay in touch, and let me know when you'll be back this way?