That scene is enough for me. Ryou was embarrassed about it, but she was totally fine with the idea. And the natural way in which she answered Sunohara's question "What difference does gender make?" just cinches it even further.
Considering the type of show it is I'm surprised they didn't play with that subtext-made-plaintext any further...
But then again I guess that's what fanfiction is for!
Edit: Currently having mental images of Ryou and Nagisa... and this is not helping things!
