Yeah, it was actually pretty interesting that almost every time Jigglypuff sang the group to fall asleep, Ash and Misty manage to get close or even on top of each other even though they originally were standing several meters away. Maybe that was just little teasing from animators' side, I don't know.
Speaking about Pokeshippy moments that I don't often hear or read talking about. The first one that comes to my mind is the episode "Tentacool and Tentacruel". There was that one scene where Tentacruel caused that huge tsunami and Ash leaded Misty away from it by holding her hand. Later in the same episode Ash got a bit worried about Misty, since she suddenly disappeared to stop Tentacruel. Overall all the moments where Ash showed even tiniest bit of concern towards Misty were very cute.
What really got me was also that particular scene in "Here comes the Squirtle Squad" where Ash returned back after bying Pikachu's potion in the city. But when he got back to the cave where the Squirtle Squad with Meowth and others were supposed to be waiting for him, it was empty. Ash got extremely concerned about Misty and thought that something bad happened to her. Actually in the Japanese version Squirtle threatened to execute Misty if Ash didn't come back in time. The dubbed version of that scene was kinda.. weird because of the dialogue change but any way, I myself consider that as quite a big hint from Ash's side, because he pretty rarely shows huge concern or even some kind of fear of losing his friend. Besides, he got very angry at the Squirtle squad for doing something like that to Misty even though he came back in time as promised, and he wasn't as worried about Pikachu as he was about Misty, at least in the Japanese version.