What about if you go for a Green Checkered Shirt, a Leprechaun Hat (from the Rare Token Store) and maybe something like Sous Chef's Trousers or Ringmaster Pants? You could choose your own boot/glove/neck gear to suit and perhaps even wear some wings.
I guess it's all down to personal taste really, but I do find the checkered shirts work well with RIngmaster Pants/Sous Chef's Trousers.
If you can afford one, a green phat always goes well with 120 herb cape. Guthix bow is a good keepsake to go on the weapon slot, and robin hood outfit as well.