Having an unlimited bandwidth system with this sort of capacity would be expensive. We recommend that you go for one of our pay as you go servers. We can increase the listener capacity past 500 after you sign up if you send us an email.
The unlimited bandwidth system is more for when you know exactly what capacity you need. The pay as you go system is for when you start out and want to gauge the response to your listeners without having much of a cap. We can transfer you between the system if need be once signed up.