Asterisk experts..........Intruiging

I am engaged in research regarding a unique telecommunications network. This network must allow approximately one thousand calls per hour and it must function like a massive voicemail system; allowing each user access to a private “voicemail box” (using passwords and pin numbers) where the user can record new messages, continue old messages or delete messages. The maximum message length per user must be no more than 15 minutes and the network must allow the user to download their message to an MP3 format or CD format at the users’ discretion. How would an expert suggest a network such as this be set-up using a PBX such as Asterisk?

this would be a good place to start
google.com/search?hl=en&clie … tnG=Search