Hi 
Is it possible to play with the UV texture coords doing a GUI.DrawTexture call? I want to do something like this http://www.youtube.com/watch?v=lSB3TwFG15g see in minute 1:13 when the buttons are loading before being able to use them. What would be the best way to implent this?
No there is no way to do that.
But you could use SpriteUI / GUIManager for example
Yep that’s another option. I tried to do it with the BeginGroup stuff and it worked but I think it is really an ugly way to do this 
Groups are naturally an option, thats right.
But I personally prefer the flexibility and performance benefits of SpriteUI, guess I got too used to it due to iphone development.