I recently purchased a RVS4000. I am looking to purchase a 4 to 8 port Gigabit switch as well. I noticed the RVS4000 has grooves on the top of it that look like they were designed to allow another device to be stacked on top of it. Does anyone know what device or devices were designed to stack on top of the RVS4000? It looks like the EG005W or EG008W might be made for this based on size and design but I can't find any documentation on this.