RE: rectangle operations - narrowing?

[Drew Adams]

        I was thinking of perhaps doing some stuff on 
        rectangular areas of text (e.g. columns of text)
        - in particular, searching over them, and I'd like
        to know what, if anything already exists for this,
        before I start trying to roll my own. I looked at the 
        Emacs manual Rectangles stuff and library rect.el,
        but I didn't notice what I'm looking for.
    
    Did you also look at cua-rect?

I haven't yet, but I will. Thanks for mentioning it.