So I've been watching online streams with SKT interviews and I've heard that the following are the new 2017 SKT skins so far (but don't quote me on these since I am not sure if these are correct)
Duke: SKT Ekko (Confirmed)
Blank: SKT Zac (Confirmed)
Faker: SKT Syndra (Confirmed)
Bengi: SKT Olaf (Confirmed)
Bang: SKT Jhin (Confirmed)
Wolf: SKT Nami (Confirmed)
I'll post a source as soon as I find it
Edit: Here's the source - http://sports.media.daum.net/sports/esports/newsview?newsId=20161031104524183
Since it is in Korean, I'll translate an excerpt from it
"During the discussion with Coaching Staff, the members of SKT have mentioned the champions that they want skins for. Faker wants either SKT Ahri or Syndra, Duke wants Gnar or Ekko, 2 Junglers have not yet decided, Bang has chosen Jhin, and Wolf has chosen Nami," (Daily eSports)
Edit (12/6/2016): SKT Ekko has been confirmed - Source: https://www.youtube.com/watch?v=YVyfHbh-Iz4
(38:42 - Duke: "...at the end I chose Ekko but I don't know if they will make it or not")
Edit (3/21/2017): Okay some people are getting confused. These picks are for Season 6 Worlds. I just said 2017 because that's the year (THIS YEAR!!! :D) the skins are being released in.
Edit (4/17/2017): This is a month old, and I forgot to update this when this vid came out. But, Bang confirmed his pick 'Jhin' himself in his stream.
Additionally, the proof video of SKT Interview I attached few months back also had Wolf revealing his pick to be Nami, confirming the rumors. Furthermore, Bang in the video attached to this edit again says the same.
Edit: 6/9/2017 - A new thread dealing with the brand new spoilers of the skins are now posted: https://boards.na.leagueoflegends.com/en/c/story-art/fOLtrbLY-2017-skt-skins-spoiler
SKT Syndra and SKT Olaf has been confirmed officially, as well as other skins for the second time. Video uploaded on LoL NA YouTube channel - www.youtube.com/leagueoflegends