By the maker of the famous T-DAC, the new Rpi-DAC which uses only P5, leaving P1 for other purposes.
Quote from the maker on Volumio forum:
"If your are looking for a cost-effective alternative of HiFiBerry, a board with more options (e.g. very-low-noise DAC LDO or to power RPi and your extensions, to have P1 connector free on RPi) - please check this out:
http://www.tjaekel.com/T-DAC/raspi_rca.html
tjaekel"
Seems like a good option to me, keeping the P1 header available for powering the Pi, LCD display, etc.