Yes!
For audio purposes, many router boards these days come with some
audio features or at least the option to attach an audio codec
(such as Wolfson WM8731) to it. You could either use a router
with audio inputs/outputs or use a devboard (eg. VoCore2) and
attach a codec to its i2s/pcm interface and i2c bus yourself.
Performance-wise it's just much smarter to add audio features to
a networking device than adding networking (esp. mesh!) features to
a media-playback-centric device.
Just a thought, is it possible to add an USB audio dongle to a router (with USB port of course)?