VOIP can be expanded to that size and larger.
I am not an expert on that system, but I think if you were to post your issues on forum940, you may get some answers you can use.
There are some tricks we can use to link Multiple Legend/Magix systems (AT A SINGLE LOCATION) together to accommodate a lot more than 500 Extensisons, but it is my understanding the IP Office can do that task in a more economical manner.
However, if the requirement is to have a total of 500 Extensions spread out over MULTIPLE LOCATIONS, then the Merlin Legend/Magix can be the IDEAL soulution.
So, are you talking about 1 location with 500 Extensions or several locations with a total of 500 extensions?[/color blue]