In case you are keeping tab on when all GSN originals are filming, Skin Wars: Fresh Paint is officially underway. According to RuPaul, the series is filming this week.
Skin Wars completed filming its third season last week. The third season of Skin Wars is expected in January. It is unknown when Skin Wars: Fresh Paint will make it to air, but it is very likely that Skin Wars: Fresh Paint will make it sometime during the upcoming Skin Wars run, if not even at the start of Skin Wars Season 3 in January.
Idiotest is currently filming its third season and expected very early next year (most likely January/February, like Skin Wars: Fresh Paint). Winsanity is filming early next year and is expected as a spring/summer start.