I'm not sure if I'd call it molasses (wouldn't molasses be cooked?) , but I'll second Phonecia. Several brands of pomagranite syrup under the counter in front of the bread (facing outward) at Phonecia on S Lamar.
I'm pretty sure Central Market sells it as well. One of the classes I took at the cooking school had a recipe that required this ingredient and the chef mentioned they sold it downstairs, I believe by the sodas. Ask them to show you where.