If you have a digital trunk tracking scanner, then yes you can feed VIPER.
There is a device called the Barix Instreamer
that is designed solely for pumping out a MP3 stream from an audio source to an audio server. There are detailed instructions for this device in the wiki.
Another option is to use a thin client. These are basically very small computers used as work stations at the enterprise level and do not typically contain any moving parts making them stable, quiet and energy efficient. They can be had for around $50 on ebay or the like. Search the forums here for thin clients; there are lots of threads regarding them.