@Jacob, this part of GNS3 "users have to provide their own IOS/IPS/PIX/ASA/JunOS to use with GNS3"? Does it mean students would have to buy a router and use GNS3?
gns3 with cisco ios you can build upto a ccie level lab and infact you can build a voice lab what you wont have is support for mgcp.
You can also include juniper switches. Thats all one needs