Could support for sound cards be included.
Many telephone systems have the capability of accepting sound input for the 'On Hold' functionality. The E-Smith system could be perfect for hooking onto this and playing MP3's etc.
An additional advantage is that one could create sound snippets on MP3 and play them. Things like announcements on products, holiday notices, basically anything you wanted read. Just add or change the playlist and it will cycle for you.
If you also wanted to change the messages between opening/closing/weekends then a cron entry could swap the playlists for you.
Just an idea to increase the flexibility.
Dave