On reddit someone said they should get released today.
To quote a comment: "According to Garena, TPA SKIN will be available today, May 24th, @10:00 to all servers! Further info from Garena, there are two bundles for the TPA SKINS. 1st Bundle . 5 skins + 5 champs 2nd Bundle. 5 Skins"
Not sure which "10:00" is meant here, though.
Another poster said, the are already released in Taiwan.
I am currently thinking whether I should buy the bundle with champions and skins, if the bundles will exist outside Taiwan too.
Currently I don't own any of the champions, though I am interested in Nunu and Ezreal. I could maybe buy Nunu with IP, but then I really have to start saving for runes.
Orianna would be a "nice to have" champion for me, I'm just not sure about Shen and Mundo.
I guess it will depend on the prize.