Your comments

This is quite trivial to make, and isn't a question to be asked here. Please try to direct "How do I...?" questions to the forums instead :)

Here are two things to get you started though:
http://acegikmo.com/shaderforge/nodes/?search=Blen...
http://acegikmo.com/shaderforge/wiki/index.php?title=UV_Scaling_%26_Offset
Per-node precision has now been implemented in RC 0.37:

This has now been implemented in RC 0.37 :)
You can now enable variable precision and name control in the settings menu, to pop up this extra panel on all nodes that will define a variable.

Tex2D doesn't work in vert on OpenGL, but Tex2Dlod should. Which one is it using?
Does the shader code contain #pragma glsl ?
It sounds as if you simply forgot to assign the mask in the material inspector. Although I suppose there could be a texture limit you're hitting as well