I have never seen one... not to say that there is not. But because structure can vary so much between two dogs I think that it would be really hard to guestimate height or length. I held another 2.5lb yorkie the other day, he was even the same age as Maddie they were equal in weight but he was a whole head taller than her and even a bit longer, she is sturdy and compact, very solid little dog and he was finer boned and felt more fragile even though he was larger. If there is a chart though I would love to have a link
it is always fun to compare and guess