In Grim001's Object Engine demo, he had the doodads as units which were drag-selectable, but not individually selectable. Someone told me the method, but I forgot/am not sure of it anymore.
Does it have anything to do with giving a unit Locust, then making it Chaos Morph into itself?
@Naakaloh, I know for a fact that selection scale doesn't affect how big a unit's selection box is. It will only affect how big the lil' green circle is.
@Diod, MPQ2K has some funky error with extracting from things protected by VMO.