Outside of appearing stupid... is double instancing possible ? If your branches are instanced (this is btw the approach Alex Roman took as well if you read his book), can you then instance the whole "group" without some issues (3dsMax or rendering side) ? Or scatter it ?
Most trees on market are single-mesh, but that is exactly why they don't look like trees at all. You can't make sub 10-milion poly tree that looks like tree from anywhere else than aerial view.