Sometimes it happens to me, that I want to make the tiling of a texture lower than 1.0, but it seems not possible in the Editor Material Componenet (anymore), only increments are allowed.
If i remember correctly it was possible in Unity 2.1.
You should just be able to type in values of less than 1.0. For example, 0.5 just worked for me, resulting in only one half of the texture being visible on my object.
If this isn't working for you, it sounds like a bug and should probably be reported using the bug reporter too.