Earlier rumors were just confirmed at the New York Comic Con preview party - wave 4 consists of Dagobah Luke, Dagobah Yoda, Toryn Farr, Snowspeeder Pilot Wedge, Snowtrooper Commander, and ROTS Darth Vader. Thankfully, almost every figure looks to be made of completely new parts, though Wedge looks like he's based on Snowspeeder Luke, and Toryn might use some Hoth Leia pieces. Aside from Luke's ginormous backpack and the fact that I was hoping for a crispy Anakin over an armored Vader, these all look most impressive. Yoda in particular looks to be a huge step forward from previous releases.
SirSteve's coverage includes the figures starting on this page. JediTempleArchives and Star Wars Action News posted photos on their Facebook feeds as well.