Here is an actual study that tracked muscle gain (presumably with a calorie deficit).
http://thefactsaboutfitness.com/print/20jun2004.htm
Normal:
Total calories 2,540 calories
Protein 113 grams (20% of total calories)
Carbohydrate 306 grams (48% of total calories)
Fat 91 grams (32% of total calories)
Low-carbohydrate:
Total calories 2,334 calories
Protein 176 grams (30% of total calories)
Carbohydrate 46 grams (8% of total calories)
Fat 157 grams (62% of total calories)
And the result?
Total fat loss at the end of the six-week study was just over seven pounds in the low-carbohydrate group. The group following their normal diet lost no weight.
The men following the low carb diet diet gained just over two pounds of muscle. The control group, on the other hand, gained just under one pound.
In other words the "low carbers" gained 2 pounds of muscle in 6 weeks.