I was really damn disappointed when I equipped the power armors from this mod to see that they didn't change the player sprite at all, the inventory sprites look great though, is changing the player's appearance to fit the sprite in the inventory planned at some point or is changing the player's appearance impossible ?

It is planned but it might be a while, I have a friend working on them in his spare time but there are a lot that need doing, and he doesn't have much time lately, might commission someone if it takes too long, but it's not a huge priority until Factorio officially 'releases'.

Awesome, I haven't seen a single mod that brings changes to the ingame player sprite so I thought that might not be possible. Good to know I was wrong on that.

There are a few around that do it, at least one that I know of for sure, but it's a lot more work then just cobbling together a few icons for everything else unfortunately.