According to the Pier Solar page at Watermelon’s MagicalGameFactory the Dreamcast version of Pier Solar HD has now been given an official release date. The game will ship out 03/25/2014.
Official Pier Solar HD trailer (Nintendo WiiU version):
The Dreamcast version (on which the other versions for WiiU/PS4/etc. are based on) will be distributed by Watermelon itself. You can pre-order the game here: http://magicalgamefactory.com/en/factory/pier-solar_1/