Most Helpful Guy
He's making jokes about it to test your feelings because he is afraid you don't feel the same way. He sees clues you feel the same but you never acknowledge them overtly so he doesn't want to ruin your friendship. The big clue, he hasn't dated anyone else. He mentions dating to see your reaction to see if you make the normal "friend cues" about advice and such. A woman who is only a friend will usually try to set you up with one of her friends or family. He is also trying to respect your lack of interest by dating other girls, but it doesn't go anywhere because he is always thinking about you.
Guys can be extremely oblivious when it comes to women, we are very different creatures. But woman can be oblivious too ;) I never say anything definitive based on these things, I give different points of view, but I would be SHOCKED if he wasn't interested in you. All you have mentioned are classic man sign hunting for the elusive female psyche.1THIS IS NOT RELEVANT ANYMORE