No, wasn't suggesting a 10 star system that would be way too cluttered. Was thinking of one extra star button set slightly to the right of the 5 stars that when clicked/tapped on, it fills halfway. So, for 3 and a half stars you would press 3 stars and the extra half star button. I understand that it still might not be able to be done but that is what I was suggesting.Essentially what you're after is a 10 Star system rather than 5.
I'm unlikely to go for this, as I think a 5 star system is easier for most people to decide upon a rating, so I'm going to mark it as 'not planned' for now. (sorry!)