May I ask a related question as I have just stumbled into a similar problem and thought I’d save starting a new thread.
I come from a Lightwave background and there, you have 'edge / stop / repeat & mirror options for the image mapping.
Obviously the ‘standard’ is repeat with the above option creating the ‘stop’ action, however, how would one do mirrored textures and ‘edge’? (where the last pixel on each edge covers the remainder of the faces selected for the UV map). Or are these options not avialable in Cycles? (They all seem to be available in BI).