I just did a little experiment. In one hour of pure knitting time (and some tv watching) I knitted up 5 grams of sock yarn. The first sock of my Last Pair for 2007 weighs 41 grams and I have about 15 grams knitted up on the second sock. So I need to knit up about 25 grams more... 5 hours. Piece of cake.
(yes it is)