Reserve 4 Tbs. butter. Heat the rest of it in a skillet until bubbling. Saute the onions and celery until they begin to brown at the edges.
Add the green onions, thyme, salt, pepper, and stock. Stir and bring to a light boil.
Remove the pan from the heat. Add the bread and the bread crumbs and mix well. Allow to cool.
Measure 2 1/2 cups of the bread mixture into a large bowl. Break it up with your fingers. Add the crabmeat. Very gently combine the crabmeat into the bread mixture.
Spoon the stuffing into shells. Melt the remaining butter and brush it over each stuffed crab. Bake in the preheated oven for about 10 minutes. They will not really brown, but they will start looking toasty.