User Christahope on the Arena recently found these pictures of Derpy on taobao, dressed up in a San Diego Comic Con box! At the moment there’s nothing to confirm it as real or false, however there’s a fairly good chance it is legit, and Derpy will be heading to SDCC.
Note that SDCC ponies generally don’t have names- clever, Hasbro. Clever.
No word on any specifics like price, ect. SDCC ponies are usually around $16 (I think), but if I’m not mistaken this will be the first G4 one, so it could be different.
Whole Arena thread here