@Gomenasai  
Pinkie Pie would definitely become a chubby pony when she gets older.
 
And yeah, I like the “chubby pony model,” (it’s nice to see different body types sometimes, plus chubby ponies are adorable) but so far they only use it for this character, Rarity’s/Sweetie’s Mother, Mrs. Cake, and a generic bowler pony from the episode “Cutie Pox.”  
Babs Seed also kinda counts, ‘cause she is also a tiny bit chubbier, and taller then the CMC, and other young ponies we’ve seen on the show.

Mrs. Cake’s body should be used more often on BG ponies.  
Maybe this is what mane 6 will look like in 20-30 years.

@GodheadInspector  
She is adorable, she needs more fanart.

D’aaaawwwww, she’s fat and adorable.~<3

she’s actually a little chubby. cute.