Your pictures do look like pendula first and hanging basket second. I think the last few years that Antonelli's were open that they produced the seed and another company raised the tubers. I sometimes see someone try to ID a Tuberous Begonia. There are named varieties that are very expensive as they are produced vegetatively. Places like White Flower Farm and Black and Langdon offered them. Several local nurseries carried the American Hybrids but I haven't seen them the last few years. I wonder if they are still avaiable? The hybrid tubers were far less expensive and just as nice. I love Tuberous Begonias