Has anyone tried the Banana Pi?
http://liliputing.com/2014/04/banana-pi ... emory.html
It's got a 1 GHz Allwinner A20 dual-core ARM Cortex-A7 processor, 1GB RAM, gigabit ethernet and even an IR receiver.
It doesn't support I2S from what I understand, but perhaps it could improve things with USB DACs.