Text fields where text will scale along with resolution.

We would like to create an input text field that scales along with the scene's content. I thought of using TextMesh like all the text we have in our game but I did not find any doc about making it a editable text field. And GUI.TextField will not scale like we want.

Is it there a way to achieve that?

GUI.Textfield will scale if you use GUI.matrix. The docs on that aren't exactly overflowing with detail, but there are some examples on the forums (like this, 10th post there).