you can also buy a soekris already assembled and in a housing, that will be way below 20k.
you are only going to go over 20k if you do a dual board setup. if single board way below 20k and better than all the DAC's mentioned so far.
i am running it as a plankie in single board as i wait for all the other bits to arrive.
i would recommend that for anyone looking for a DAC in the -20k range they get the seokris because it is a true performer in its single board setup.