All you can eat crablegs in Lafayette

The easiest way is to pick up some clusters from Albertson's (for instance) when they're on sale, put them in the freezer and steam them yourself whenever you like. I always have some snow crab legs in the freezer because they're so very easy to prepare at home.

As bbrou mentioned, Hai Nam is the only place I can think of. I haven't been to Golden Wok since they moved years ago, but they also used to feature them.

If you're not particular, blue crab legs are everywhere right now.

ETA: If you do pick some up at the store with the intent of putting them directly into your freezer which is what I do most of the time, ask if they have any in their back freezer still frozen, and chances are they will.