I don't know of anyone who intentionally grows tomato plants in low light conditions, specifically with the intent of creating a longer stem. While I doubt the practice would cause major or visible harm to a plant, it seems to me that it wouldn't necessarily benefit the plant, either.
Many people simply remove the lower stems on their tomato plants, and then plant them deeply. Plants handled in such a way develop large root systems.
While I have no scientific studies that I can offer in support of my opinion, I personally feel that stress during the period of developmental growth does, or at least can, weaken a plant by reducing its stored resources, leaving it less able to resist future attacks by insects and diseases. All just my personal opinion, though.
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams