From what I can tell, the answer is no, but is there a way to manually select the logo for different cover sheets? It seems unbelievable that we can only use one.
To directly answer your question, I believe you are correct. (We may be proven otherwise )
However, a report images repository was added in R8+ to InfoCenter.
This allows images to be uploaded and leveraged very similar to report parts, and may work for what you are trying to do: