The one with with knight with the mochi hammer, right? Yea that one was cool.
I compiled a whole list of stories and ideas - the tongue-cut-swallow was on it - and also asked the in-laws for their favourites. Ideas involving torii gates, fox yokai, lion-dogs.
Besides myths, on my list are also a bunch of knights - the traditional samurai, but also warrior-monk, shinobi, etc. Also think some castle, shrine sites would be cool. In fact, I had trouble coming up with a myth for urashima taro, but just today realised it would make an interesting site.