Sort of. One character has an ultimate that renders them invisible underneath a cloud and thus can't be hit by auto attacks. They can be hit by aoe spells, like akali under her bubble thing. It lasts him about 4 seconds in dota I think? But he doesn't get any special abilities to go with it; he's just unable to be autoattacked. You always know where he is because he's under a cloud that is always above him.
https://www.youtube.com/watch?v=khLWZhuOLAw
So now that I think about it, no there isn't anyone who is completely undetectable by the true sight.
http://dota2.gamepedia.com/Invisibility
For the record, there are 23 different items and abilities that grant true sight and 29 items and abilities that give invisibility.
Point is, there are many, MANY ways to counter-play invisibility, from built-in abilities to purchasable items. I will take a wait-and-see approach to having 0 counter-play options for these champs. Drawing inspiration from the most casual of the moba games on the market (HoTS) does not instill me with any confidence. But as long as they don't get any power spikes by coming out of invisibility, I'm sure they can balance it to some degree. I just don't like the idea of "surprise! 3 in your lane now" mechanics without any way to give yourself a good opportunity to you know...NOT get ganked by them.