Audio analog to digital ADC for bench

I have been searching an analog to digital ADC converter for testing DACs with no results for my askings.

The idea is to have an "bench" ADC and feed it with a wave generator (sine, square, triangle, arbitrary, etc.) for testing DACs with SPDIF or I2S or other formats (Right Justified, Left Justified, etc.)

It would be good idea as a bonus, to have DSD output too.

It no seems very difficult to design one with PCM4222, AKM or another chip, but i'm too lazy for begin the task.

Anybody know is there any ADC suitable or project?
I have no idea about raspberry pi or Beagle Bone.
If it is easy or there is some project that were close to my needs I could to have a try.
Another red line is the price. I know that Altor Audio sells the JKG generator that is a very wonderful thing, but is costs 520 USD, and I want some cheap gear.