you can call Cassones bakery in Port Chester, NY. They sell the rolls (small, medium and large). If you go there it's about $2 per dozen. They bake them and sell them in bulk.Give them a call. They deliver to stores and supermarkets. I guess that would depend on the quantity ordered.
I love Cassone hard rolls and Italian bread (I grew up in Westchester county). However, from my days working in a deli that used Cassone hard rolls, they are very perishable (the real hard rolls, not the ones in the plastic bags) and don't last into the next day unless you freeze them. Delis get them delivered fresh every day. Maybe it's time for a road trip!