Ok. I admit this is perhaps a difficult one but when I skatter billboard based items it could be handy if you had thumbnails next to objects names in the list.
Or, at least, being able to capture snapshots of the object when you define it to skatter… even more difficult? 
This might actually be possible.
Using the Ruby API, there is a way to save the thumbnails that you see in SketchUp’s Components window. Is that what you want?
Yes, I think this is already a great step forward, to be able to visually identify what species of plant (or object) you’re selecting.