This is good news: Alliance Powersports is expecting a new container shipment of SYM bikes ('12 models) and parts to be on its way within 30 days, including a good quantity of Symba bench seats and the rear racks that fit with them.
Now would probably be a good time to contact your dealer and put in an order for one of the new and improved bench seats. According to photos I've seen of the new seat, its much taller and therefore probably provides more cushioning for a softer ride. That was one of my concerns about the original design - the padding was rather thin.
Also, the new rear rack that is designed to fit with the bench seat installed should be available soon. Previously, you had to make a choice: solo seat and rack, or bench seat and no rack. Now you can have both!