Shader: Get "normalized" vertex position

I need to get the normalized positions of the vertices.

In other words, when I have a model that has a size of (2, 4) and I get a vertex with a position of (1, 4) I want to recalculate the position to (0.5, 1).

Is this somehow possible without passing the models size by script?

In 2.6, Unity will always scale models before rendering. So, you will get a position of (4, 16, ?) for your vertex in that case. So, there should never be a need to get the scale in the shader. What are you trying to do?

Unity 3.0 will have native rendering for uniformly scaled meshes, with the inverse scale passed in the .w coordinate of the camera position for shaders which need it.