So far Maud is the only one of Pinkie’s sisters we have ever seen anywhere other than the rock farm and ever since the establishment of one day for each sister at some place in Equestria every year in the episode “The gift of Maud Pie” I am hoping for that set up to be used. Apart from all Equestria encompassing adventures with one sister a little meetup of all sisters in Ponyville too would be an interesting idea. I really wonder about how for example Rainbow Dash and Limestone (both with a bit of a temper) and Fluttershy and Marble might get along.  
Anyway, with Equestria Daily’s Pinkie Pie Day 2018 comming up (on October, 7th) I burned an image of the four Pie sisters trotting into Ponyville into a wooden board. Pinkie’s pose is heavily inspired by this amazing image by SpainFischer.  
This is a work in progress / outlines only version of the image.