How to make an arbitrarily-shaped selection of objects?

Someone replied to my original question in the regular Illustrator forum and suggested I post here, seeing if anyone has written or knows how to write a script to do this. Pointers or help are much appreciated!

I have a grid of objects—say, tiny squares. I'd like to make arbitrarily-shaped selections of those objects—for instance, select a star-shaped group of the squares. Or a circle-shaped group of the squares. Or use text paths to select letter-shaped groups of the squares.

I could imagine a utility that lets me choose an arbitrary shape/path, and then turn that into a selection of objects on the canvas. Is this possible?

Right now I'm stuck using the lasso tool to hand-draw shape selections but it's not accurate enough for what I need to do.