Is it possible to create an textured translucent PNG? I'm attempting to separate the texture from the color - allowing me to define the color, ultimately, via my CSS.
Yes, it is possible.
What you might want to do in photoshop ( or other programs ):
Limiting factor here is Blend modes which you can't really use extensively in this case, opacity and extra coloring can make up for that though.
Here's an example of it http://jsfiddle.net/y7SLu/
The texture image: